I'm converting my 1958 Buick over to electric wipers with delay and automatic "wipe on wash" functionality, and in the process I'm trying to figure out how to integrate the new electricals with the entirely non-electric original wiper controls so the driver experience is relatively unchanged. If you haven't already, you should read my Delay Wipers page about delay wiper conversions in general to get a background for this page - this started as a small example section on that page and has grown into this page over time as I have done more work and encountered more issues that needed to be dealt with. The conversion is not yet complete (I'm still in the planning stages on some of it and in the process of doing other things), so this page will be updated with pictures and details as I get them.
Wiper Motor Replacement
The major problem I faced is that the car was originally equipped with vacuum powered wipers. They are notoriously unreliable and fussy, so the first step up was to find way to convert them to electric wipers. Basically, I saw an ad for "bolt in vacuum to electric wiper conversions with a delay option" in a "hot rod" magazine, and I called New Port Engineering to talk to them about it. I compared the details they sent me with the factory manuals and the factory wiper switch assembly to figure out the possible plans of action. The kit converts the wiper motor itself from vacuum to electric and is supposed to be a "bolt in" conversion for the motor. Once I get the motor mounted and proven to be working, I should be in good shape - the motor and wiper transmission engagement is the biggest functional piece that I cannot readily engineer myself. With the motor in place, I will have a reliable electric wiper setup and will have reduced the problem to switches, electronic controls, and wiring - stuff that I can do myself.
Removal of the old vacuum wiper motor went smoothly, but, unfortunately, the installation of the new wiper motor did not go so smoothly. The basic fit is there, but the bracket the holds the motor and is supposed to bolt down to the original mounting points for the vacuum motor was about 1/4" too short on the unit I originally received. The drive block that engages the wiper transmission was in the right location relative to the mounting holes in the bracket and was the right size, but the amount that drive block stuck out relative to the mounting brackets on the motor was wrong - it stuck out about 1/4" too far. Based on a hand-corrected year in the application/install notes I got with the unit, I had a suspicion I may have been sent the wrong one.
I called Newport's tech help line to see what they would say, and the very helpful person I spoke to said the 1957 and 1958 units were different in exactly the way I noted above - the drive block on the 1958 units needed to stick out about 1/4" further. So, they did send me what they believed to be a 1958 unit, the best I can figure is I had an early production 1958 unit that used some 1957 parts. Joy. I shipped the electric wiper motor and my original vacuum wiper motor back to Newport and they promptly confirmed that a 1957-style conversion would work and shipped me back a new electric wiper motor and my original vacuum wiper motor. Very nice folks, and I'm pretty happy with the system as delivered. I will need to properly adjust the motor and wiper arms to be perfect, but I'm attributing that more to the fact that it's a hybrid 1957/1958 system from the factory than to their initial setup.
The conversion kit has all of the needed wiring for a non-delay installation, but the switch they supply is not a factory-style switch for my vehicle. It is a simple three position rotary switch (Off-Low-High) and works quite nicely for what it is, but the factory wiper switch on this car is a very unique lever and cable arrangement that simply controls a cable that goes out to the wiper motor. Internally in the wiper motor, the cable movement controls a variable sized orifice on the vacuum line going into the vacuum motor and it allows for infinitely variable wiper speeds. (Seriously - it's pretty cool.) There is also a pushbutton that controls the wash function. It does this by venting a vacuum line to atmospheric pressure, which engages the washer pump and causes it to pump wiper fluid onto the glass for as long as you hold down the button. Physically, this switch fits into a unique location in the dash and one of the many chrome pieces that give the interior it's unique look. Functionally, the switch is also unique - it is entirely mechanical and not electrical.
My basic plan of attack here is to get the motor is in place, then hook it up to make it work with the rotary switch, then hook up a modified/custom switch that fits into the factory location, and then hook up my custom built delay and automatic "wipe on wash" circuitry. I could have purchased the delay wiper kit from Newport Engineering, but the delay switch they provide is a rotary switch similar to the one used on a 1969 Cougar - you rotate the switch from off into an area that controls the delay, then you can rotate it further to the "Low" and "High" positions. It's not directly compatible with my original wiper switch - see the pictures below for details - but I could make it functional easily. Making it integrate with the stock dash and switch is an entire story unto itself. The good news is that they control the delay from the switch side, so adding delay wipers sometime after I get the electric wiper conversion done won't be too hard. I will still have to solve the functional issues with the switch (aka, how do I control it as a driver) and mounting/packaging issues with keeping the car looking reasonably stock while making things work easily, while using parts I can actually get my hands on. I could have custom switches built, but that costs big money for one-off units. I have lots of options for the switch and how I use it, ranging from just mounting the new switch under the dash (aka, just use what they gave me) on up to some really wild custom arrangements that I've brainstormed about below. I pretty much know I will need to engineer my own switch solution, and the only question is what I will end up doing. Their instructions specify a 4 amp fuse for the system, so I need to make sure all of my parts that control the wipers are rated for at least 4 amps.
One switch option is to build a bracket under the dash to meld the factory cable arrangement to the electrical switch so that when you pull on the factory wiper control lever it moves the switch supplied in the conversion kit to control the new wiper motor. The switch would be hidden from view under the dash and the factory switch would be unchanged. Physically and mechanically, this shouldn't be too difficult to do, but will take some time and thinking to pull it off as well as some careful fabrication to make sure it all works correctly and reliably. The pushbutton on the front of the factory switch would still control the washers, but it would be replaced internally by a modern momentary pushbutton. Overall, this might work, but there are two functional drawbacks to doing it this way. The first drawback is the the delay is not controllable separately from the "on-off" control of the wipers. Most rainy days would end up using a similar delay, so it's nice to just leave the delay period set and just turn on the wipers to the "delay" speed, but still be able to adjust it as needed from there. In this system, you have to move the wiper control through the various delay periods to get what you want. The second drawback is the limited "throw" of the factory lever. It may not be enough to reliably control the delay period and have the "off", "low", and "high" positions available. Based on some initial research and my distaste for this style of switch, I will not be pursuing this option further.
Another custom switch option is a variation on the above option that uses the factory lever to only control the selection of the "speed" ("off", "delay", "low", and "high") along with a second control in the dash somewhere to control the delay. I could use the above idea to hook up a switch to the cable, or I could gut and modify the factory switch housing to mount a modern 4-position slide style switch behind it and epoxy the original handle to it to use for the speed control. The washers would be controlled as noted above via a modern momentary pushbutton mounted inside the factory wiper switch housing. The drawbacks here are that the second delay control would have to be integrated into the dash somewhere and that the controls would be physically separated and non-intuitive to use. I also need to locate and mount a specialty slide switch into the existing switch housing.
A variation on the previous option would use a rotary potentiometer combined with the wiper pushbutton to control the delay. The rotation sets the delay, and pushing in on the button would control the washers. This would eliminate the separate control elsewhere in the dash and keep everything in one place. The mounting of the slide style switch is the same as above. The problem here is that I would also need to locate a specialty potentiometer and pushbutton switch combination that will 1) fit into the existing location, 2) have the right resistance rating to work with the delay circuit, 3) Have the correct rotational "sweep" to work within the existing housing, and 4) be the proper electrical setup to control the washers.
I will end up going with one of the two last options. The third "all in one" option is ideal, but which one I pick will depend largely on my ability (or luck, as the case may be) to find the combination pushbutton/potentiometer I need to make it the "all in one" option work.
Custom Switch Creation
Here are some close-up pictures of the switch when removed from the vehicle. It mounts into the short area of the dash that curves out on the drivers side of the car to the left of the steering wheel. When driving the car, you would use the controls with your left hand - they're about 3"-6" to the left of the steering wheel and about the same height and can be clearly seen in this picture. Below the pictures is a diagram of the original wiper switch, as viewed from the top.
Both of my possible options at this point require me to source and mount a lever or slide switch in the existing housing. The switch needs to have four positions ("Off", "Delay", "Low", "High") and have no more than 1.5" of travel. After much searching, I was able to locate a switch that will work for me from, of all places, Vintage Air. They sell air conditioning systems for older cars and hot rods, their fan control switches are heavy-duty (fan motors draw lots of power) and they are the proper four position lever style I need. The lever travel and length is also appropriate for what I needed here, and they are readily available as a single unit "Replacement Part" from any Vintage Air dealer under part number 11430-VUS. The switch only set me back about $12 and should work nicely. It even has mounting tabs that I can use to mount it to a custom bracket that will in turn mount to the factory switch housing. I'll have to figure out a way to get a decent handle on the lever, but at least the switch will work right.
No wiring diagrams were provided with the switch because it is intended as a replacement for an existing unit in a pre-wired system. So, I had to spend a bit of time with my trusty multi-meter and figure it out. I have it written down, but I need to draw up a pretty diagram and post it here...
Wiring and Control Circuitry
Here's the first complete circuit diagram I came up with for the new electric wipers - I drew it up before the electric wiper conversion kit arrived and I had a chance to do some bench tests on the motor wiring. It includes delay wipers and an "auto-wipe with washer" feature. I'm accumulating parts to build and test the circuit to see if it works as I think it will. Lotsa wires in there, huh? If I could get switches that would handle the required load directly, then I could eliminate the four control relays, but the chances of that are slim. Besides, using the relays to control the wiper and washer motors will allow me to use any low-power switches that I can find - that way I stand a much better chance of finding something that I can make work inside the existing wiper switch bezel/housing. They also allow me to easily interface with the electronics for the delay wipers and for the "auto-wipe on wash" features, so the relays will probably stay in the circuit no matter what switches I find.
Also, there is one small and non-obvious, but still kind of cool, feature in the wiring diagram. You can only take advantage of this feature if 1) your wiper motor has a separate wire for the power to self-park the wipers and 2) that it does not draw any power through that wire once the wipers blades are parked. If so, you should connect the self-park power wire directly to a "direct from the battery" power source (fused, of course) instead of to a power source switched with the ignition. That way the wipers will self-park when the car is turned off instead of simply stopping in mid-stroke when you turn the key off. Kudos to a friend of mine (Kevin Natale) for thinking that up while I was explaining the wiring diagram to him.
Unfortunately, once I got the conversion kit in and bench tested the new wiper motor, I found a small problem - the auto-park circuit on the new motor is designed to be energized only when the wipers are "off". If you energize it at the same time as the low or high speed leads the motor current draw increases radically and the different windings in the motor basically fight with each other - hooking it up as per the diagram above would result in heavy current draw and a very short wiper motor life. At $180 a pop for the conversion kits, that's not a good idea! This affects the switch and circuit design, as well as the "auto-park" feature.
With this knowledge in mind, I went back to my "electronic circuit" drawing board and came up with a revised diagram that works with the motor I have and preserves the "auto-park" feature. By using one additional power relay (I told you they'd come in handy to keep the circuit) and three diodes I can make the park circuit energized only if the delay, low, and high speed relays are not energized. The diodes are just one-way electrical valves, so I can tie the coil side of the delay, low, and high relays together with the diodes and use the combined output to drive a "reversed" relay so that when it is energized it opens it's contacts and prevents the park circuit from being used. This diode and relay trick would be needed with or without the cool "key-off auto-park" feature; that only depends on the power source for the park circuit being live all the time. For now, I have diagramed the circuit so that the park circuit is connected to the battery so that it will have the "key-off auto-park" feature.
Also, I checked on the availability of wiring connectors from my usual sources, and they only come in 1, 2, 3, 4, 6, and 8 wire versions. With that in mind, I updated the circuit diagram to show exactly how I would make up the combinations of connectors that I require to have the right number of wires at each connector location.
Lastly, I added two additional wires into the wiper controls section of the harness. One is a lead for the dash lights and the other is a ground. The ground should be hooked up to the switch panel I build so that it has a good solid ground and can't shock anyone if a problem develops. The lead from the dash lights will enable me to hook up a small light for the wiper controls in the future if I desire. It is an easy change now, and a hard change later, so I decided to do it just in case it is needed. I will probably just tape off the lead in the harness when I build it, but it will be there if it's needed later.
Less is Better
Now that it's "complete", it's time to go through the design and see what can be removed to decrease complexity and reduce eventual cost. As you will see in the following sections, the overall cost for the relays and other bits was a lot higher than I was expecting while planning this out, so re-working some of the wiring to use lower-cost items or fewer items will be a big win for the total cost of this work.
First up is hunting for lower cost items to replace things with. For example, the relay kit I usually use from Ron Francis handles up to 30A and I really only needs to handle 4A because that's all the wiper motor should draw. Next, the sheer number of connectors in the harness is ripe for being reduced. The connectors separating the switches from the main harness must stay - without them, removing the switches from the dash would require pulling the entire harness up and out of the switch mounting hole - not very doable. Likewise, the connector at the firewall must stay to enable you to disconnect the wiring and only have to pull one connector through the hole in the firewall if you want to remove the wiper motor for service. The connectors for the power inputs should also stay. That leaves the connectors between the relays and the harness and the connectors between the harness and the electronic circuitry as good candidates for removal. The relay connectors are redundant as you can unplug relays from their bases for replacement - that's two connectors gone. The connectors going into the circuitry are questionable - if I can get them cheap enough, I'll put them in so I can test the circuitry easily "on the bench". If I can't find them cheap enough, I'll leave them out - the final housing for the circuitry will likely be small and easily mounted under the dash. I can simply hardwire the harness into the circuitry. That means if you need to remove the harness, you have to remove the circuitry/housing along with it - not a big deal if you want to save some extra pennies.
Lastly, I can hunt for lower cost but similar items. For example, I located a wiring supplies distributor at a local swap meet who sells some of the key stuff I need lots cheaper than other places as well as some special pieces that would allow me to really build the wiring harness just like an OEM would. The morale here is to look around, ask questions of your vendors, and if needed find out who they get their stuff from. Networking this way really can work, but it takes time and effort to find the right part for your needs. Wiring is no different than anything else on your car - if you want to customize it to be "just so" and it's not the typical thing folks do to their cars, then expect to spend some time and brainpower finding what you need. But hey, it's that what hot rodding and car crafting is all about? It is to me. Tracking down wiring supplies is the same thing as hunting for the elusive speed parts or whatever else you need in salvage yards or swap meets. It's just one more example of "the thrill of the hunt" for the car guy.
The washer conversion was done using a generic replacement washer pump from the parts store. I built a small bracket for the pump and tack-welded it to the bottom of the original washer bottle bracket. It mounts the pump at an angle tilted towards the read of the car and tucks it neatly down along the inner fender where it can't be easily seen. The wiring under the hood is pretty simple - positive wire to a momentary contact switch, then out to the pump, then to ground. It's not easy to see, and once I splice it into the harness I'm building for the engine side of things it will be quite seamless.
I still need to hook up the hoses and figure out how to make a pickup that mounts in the original washer bottle. I was able to strip down the washer bottle lid by drilling out the rivets that held the stock pump assembly to it - now I can use that bare lid as a basis for my work. I have to figure out how to close up the holes in the lid - or find a replacement lid to start with. Once I get the lid figured out, I can run a pickup tube down into the jar, and have a small hose lead down to the washer pump, and another one come back up to head out to the washers. I could even use small pieces of hard line to do this with - the beauty of the jar is that it can be positioned anyway you want it in the bracket, and it slides in from the top. It also has a filler hole in in that's accessed via a small movable cover. This means that the pickup tube can come out of the lid and make a 90 degree bend to head for the edge of the jar without trouble - you can always reposition it as needed to line up with the hoses going down to the pump by repositioning the jar.
Parts List and Prices and Oh My!
Here's the full parts list for building this as I originally spec'ed this out. Items in green are already purchased, items in red are not yet purchased. Items in Yellow will not be needed, will be needed in a reduced quantity, or will be sourced differently in the "reduced" plans.
The cost of a case for the circuitry will be negligible - figure $10-$20 at Radio Shack once I build and test the circuit. The same goes for the "grommet & boot" that will go over the wiring harness where it enters the firewall - figure $10 max for that. I just need to know the size of the connector that will need to pass through the hole and the actual size of the wiring harness. IIRC, American Autowire makes and sells the right products for this.
The wire is still a bit of a wildcard - although the lengths I need are short, I need lots of different colors. Since I need 15 discreet colors to build the harness, it will be a bit spendy to make up the harness. The good news would be that I would have extra wire left over for other projects in the future, so it's not a total loss. I also might be able to scavenge some bits of pieces of other wires I have laying around to make this work, but that's a bit hit or miss and not really repeatable.
The washer delay control switch I use is also going to be a bit of a wildcard - I have not yet been able to locate and obtain a decent switch for my needs. As separate switches, they would total less than $10, but combined they could be higher.
As I mentioned above in the "Less is Better" section, the cost of this stuff adds up fast so reducing cost will be important - $200 for wiring bits on top of $200 for the basic kit is a bit hard to swallow. Based on the reduction in parts and parts substitution listed in the "Less is Better" section, here is the "reduced" parts list of stuff I have left to buy (the rest of the system stays the same). Note that this includes prices from an alternate supplier for the relays I need. Green indicates parts I have already purchased, red indicates parts I have not yet purchased. The upshot is that the cost is almost $100 lower already - and that's much more do-able on a limited budget.
One point of interest here - I found out I can source relay bases without any wires pre-installed. Bill at Arbee Distributors in Spokane, WA - (509)499-5763 cell/days or (509)466-6308 home/evenings - has a ton of great stuff, and often it's the same part, but cheaper than, say, Ron Francis. Anyways, using the bare relay bases you can custom build your harness without splicing stuff or having to fight with mangling existing relay bases. That's important in my case, for example, because all of the relays will have their "high power" inputs and their relay coil ground outputs tied together. If I had to work with wiring stubs, I'd have a spliced mess to contend with. By buying the relay bases "bare" and installing the wires I want the way I want them, I can daisy chain them all together and make a nice, neat OEM style harness out of it that has zero splices in the middle of it. How? All "connections" get made by putting two wires into the nearest terminal - see the example picture below. Move every splice in the diagrams above to the nearest connector, put two wires into the connector, and you get the idea. You run a bit more wire in some places in the harness, but the overall effect is to simplify the harness and make it more reliable by removing extra connections. You already need to make a splice/connection at each connector, and putting two wires there is no different that one if you do it correctly.
Building, Testing, and Installing
Installing the electric wiper motor on the car was first. I de-grunged the recessed area in the firewall where the wiper motor mounts (it was amazing how dirty is was), removed the existing vacuum hoses, removed the vacuum motor, and disconnected the original control cable from the motor. I then removed the factory switch from the dash along with the attached control cable - the vacuum line to the washer pump will come out along with the switch. Note that you must cap off the two vacuum source lines that come from the motor and used to connect to the motor. One line is connected to manifold vacuum, the other is connected to a vacuum pump that is part of the oil pump assembly inside the engine. Once this was done, I was ready to start assembling the new electric wiper system.
I had to build a temporary switch housing to mount under the dash so I could operate the wipers until the real controls get built. For now this is just using the switch that came with the wiper motor, but it will soon be upgraded to the switch I plan to use later on along with a basic delay control. That way I can test out the wiring and control circuits before I make the final installation of the switches - and before I have a chance to track down all the right pieces to make the final control panel. Once I get around to building the circuits and wiring, I'll take pictures of that too and post them in some semi-organized groups here.
The wiring follows the same basic route that the control cable did, and I was even able to run the wiring through the firewall using the same grommet that the control cable came through. It's a bit tight, but it works.
Page last updated 01/02/2009 01:51:39 PM