So I am planning out my power window conversion I have already purchase new window motors and have bought some used window regulators. I plan on completely making a new wiring harness for the power windows as we all know GM's wiring was a complete FAIL. The issue I am having is that I want to incorporate the OEM window switches because I want it to look like a factory install. But I don't quite understand how these switches work as they have a power input, ground, and then 4 output wires (driver switch). How can I make these switches work as a regular switch? How would I wire up relays with these switches? Where's a good switched power source to tap into that will supply enough to power the motors? Here is the OEM wiring diagram I am using. http://shbox.com/1/pwr_window_schematic.jpg Thanks guys ahead of time. Yes this is a lengthy undertaking but I want power windows, I'm tired of reaching over my dang console to roll down my passenger window.

 

I have done this before and it's quite expensive, involved, and a little time consuming. (Some of the harness parts will take several weeks to procure.)

This is completely false and if this is the premise for your wiring project, you might want to rethink things. We can talk more about the technical aspects here, but this is pure myth spread across the land by talking unicorns and vendors looking to sell snake oil and/or wiring bypass kits.

In the most basic situation - if the wiring really was "bad" or poorly designed, then these cars would have had problems off of the assembly line, which was not the case. The problem is with the original motors: our particular part is old and was first installed in GM cars in the late 1960's. The "new" motors sold of the original design still have a lot of reman content in them, which continues to cloud the landscape.

Does your car have the power window harness in it but just not plugged in? Are you going to use an express down module?

I have rebuilt these harnesses before and can help you find the tools and parts that you need. If you can answer the question on what you have in the car now, I can help steer you to the components.

You can't make these work like a regular switch and don't want to. Each unit has multiple switches/contacts in it. Besides turning the circuit on/off, it also reverses the polarity when you go up/vs. down.

Look at the passenger window switch in the diagram and you'll see it depicted as two switches, bound together, that work side-by-side as the button goes between the three positions. (Down, off, Up)

Once you understand that side, you can tackle the driver's side, which is much more complex due to the stock express down module and the fact that the passenger door switch is wired through the one on the driver's side. (This allows the passenger window to be controlled by either switch.)

 

I appreciate your input and opinion, but there's definitely a factory defect because these motors fail all the time. But you do have a good point about these "new" motors not being completely new and having reman contents in them, which could very well be the issue. I was saying the wiring was a "fail" because I was only going off of information that is floating around about them on the forums. But anyways I will be completely running a stand-alone type system. The only factory wiring I am using is the wiring harnesses from the doors because I need that for all the connectors. I drew up a schematic I think will work last night, take a look at the attachment and see what you think about it if you don't mind. I'm an electrical engineering student so I have a very good understanding about electrical theory, but I haven't graduated so I don't know everything there is to know and never will. I will need to bench test this circuit first using a ammeter to determine current draw to choose a fuse size for the circuit of course.

 

wssix99 is correct - there is nothing inherently wrong with the factory power window wiring despite what you may have read "floating around on forums". The factory motors fail frequently because they are lousy motors not because of how they're wired. Those aftermarket kits "fix" the problem using brute force by increasing current flow to the weak passenger motor and do absolutely nothing for the driver's side. The motors still fail eventually.

Your wiring diagram is essentially the factory configuration modified to add unnecessary relays. The factory switches are fully capable of handling the window motor current without the need for relays. On the other hand, the relays may be your only option simply to provide a power supply since if you don't have the factory 30A windows circuit breaker, there isn't another circuit with sufficient head room that you could tap into.

 

^ Right. The "fail" is in the motors and not the wiring. There's a lot of lipstick you can put on those pigs. (If you got new Dormans, I think you'll be happy.)

Did your car come with the stock power window harness? (I've been assuming it would.)
- If not, you'll also need the motor connectors.
- If not, are you going to splice in the stock connectors? Do you want to crimp on new terminals so you don't have to do any splicing?
- If not, have you picked out the wire that you will use? Are you going to attempt to match the stock colors/striping?

Are you going to put in an express-down module?
- If not, are you interested in changing the icon on the driver's window switch? (It will cost you a couple of bucks and its probably an **** detail, but it can be done.)


BTW - You can probably make some bucks on your rare manual regulators when you are done.

 

Okay guys I appreciate your feedback. wssix99, my car does not have any factory wiring for the power windows. I went to the junk yard and cut the wiring for the door (I cut off the harness where the door harness goes into the body) meaning that I have all the necessary connectors (motor, switches, everything). No I am not using the express down module. All connections I have to make to the door harness I bought will be soldered I do not use crimps on anything that I don't have to, I am a little confused on what you was asking here but I think this is what you were asking. No I do not want to match the factories wire colors/striping as that is way too time consuming. I have picked out the wiring, I will be using 12 gauge fused coming into the relays and 12 gauge going to the window motors. I will then use 14 gauge for the rest of the wiring. I am not sure about what gauge wire to use for the switched 12V source though, as I am not aware how much current draw there will be on that wire. And finally no I do not want to change the driver window switch icon, I am very **** but I can deal with the image. WhiteBird00 I realize the relays are not necessary but when dealing with a current draw of that magnitude I would feel much better having them. Plus without the relays power would be delivered to the switches at all times, and i only want power delivered with the switch on.

 

No need to worry about the wire gauge for the switched side since it is only connected to the coil side of the relays. They draw about 150-200ma each so 18 gauge wire is more than enough. Make sure you get quality relays with a built-in diode or else add a diode across the coil terminals with the cathode (banded end) toward the 12V+ side. This will help reduce pitting on the switch contacts. If your relay has a built-in diode then make sure you use terminal 86 for 12V+ and 85 for ground - it would work the other way around but you lose the advantage of the diode.

 

Very good.

If you look on the bottom of the stock switch connectors, you should see letters molded in to the plastic connector body. These match up to the terminal letters on the factory electrical schematic. (Unless the colors don't match up or any of the terminals pop out.)


If you look at the connectors, you'll see that they are all crimped and not soldered. Solder isn't necessarily a bad thing, but it is brittle and can crack/arc. (The typical BCM solder cracking on these cars is evidence of that.) GM recommends installing a structural crimping clamp when you solder splice wires. (See page 15-16 http://www.weber.edu/wsuimages/automotive/J-38125-620B Terminal Repair Booklet.pdf)


Did you pick out a durable automotive insulation for the wire? I recall that I purchased TXL wire when rebuilding my harnesses: https://www.kayjayco.com/catPWireSelect.htm

 

Okay so I need to place a diode across terminals 85 and 86 of the relay? Because no my relays did not come with the built in diodes. Do I need to use a silicone diode or zener diode? I am assuming a silicone.

 

Yes, the wiring which I purchased was GXL and then I purchased another type that was SXL.

 

Yes, install the diode across terminals 85 and 86. It doesn't really matter which terminal is cathode or anode as long as the cathode end is toward the 12V power source. But it is standard to install with the cathode to terminal 86 to match the way relays with internal diodes are configured.

Since rapid switching is not required, an inexpensive 1N4001 silicone diode will be quite sufficient.

 

Just in case you guys are wondering I got this install finished up this past weekend. It was pretty straight forward, the regulators were a piece of cake to install. Yet the install did take a fair bit of time to complete, there was a lot of wiring involved. But yet again I did go ahead and add some power locks as well while I was doing the power window conversion. For anyone who is wondering the power window motor draws 5 amps of current as I measured on my Fluke ammeter. Thanks for your help guys!

 

Congratulations. How is life with power windows then? Nice?

 

I'm really enjoying it to say the least. It's no where near as big of an ordeal as everyone makes it out to be to do the conversion.