Topic: 4 Relay power window installed!!

[Rick]

The "slow window" syndrome is such an incredibly common problem, I think this topic should be stickied.

[78ta]

Lee01,
I was going to try my hand at drawing this up with paint but simply haven't had time. Here are the pics of the circuits I drew up for the power lock circuit. One is a schematic showing the electrical circuitry itself. The other is the wiring schematic showing how the wires actually connect. As I mentioned earlier, there are a lot of wires crossing because both door lock switches have to control both door lock actuators. If anyone feels froggy, you're welcome to have a go at drawing it up in paint or however you see fit it if you want.
All of the wires that go to ground symbols (87A's and 86's) can be tied together and grounded.

[78ta]

I agree Rick. I had told Brett that I planned to do a write up with pics and the schematics to post on the site so that may be why he hasn't stickied the thread. That thread may be confusing in places. Unfortunately, I have a catch 22 going on with my TA. As some may know, beside the 78 TA, I also have a 70 442 and a 71 Lemans project car. On one hand, I'm very fortunate that my wife likes old cars. One the other hand, because she likes having the TA available to use anytime, I'm "forbidden" to take it out of commision during the summer months.  So it will be a little while before I can do the power window/lock swap to it and do the write on on that.    At least we can get the wiring diagrams out there for people to use now.
I got busted just the other night. I had the dash apart troubleshooting the gas gauge problem on the TA thinking it wouldn't be a problem because we'd take the 442 to the cruise that night. Of coarse, the battery in the 442 decided to take a dump. We were already late so I just threw the dash back together on the TA so we could take it and she caught me. Gas gauge works great now........

[Eagle 1]

Personally, I think the new ground to the motor makes all the difference in the world and should speed up the motor with out putting a load on the circuit.
The relays are just the icing on the cake.

[78ta]

Eagle1,
That may very well have been the case for your car. That's great that that's all yours needed. I'm sure there are many reasons for slow windows, mechanical and electrical. Dirty/sticky regulators and poor circuit design. What fixes one may not help another. If I'm going to the trouble to take my car apart to fix a PW problem or even install them from scratch, I'm going to do everything I know of to improve their performance.

[lee01]

Foir those you want power window, this ebay seller as brand new kit available.
495$
http://cgi.ebay.com/ebaymotors/1978-78-79-80-81-1981-TRANS-AM-POWER-WINDOW-KIT-NEW_W0QQcmdZViewItemQQcategoryZ140733QQihZ025QQitemZ380030684684QQrdZ1QQsspagenameZWDVW

[Rick]

The problem is that the whole original design of the GM power windows in the F-body just sucks.  It's simply BAD circuit design to run power through the control switch in any circuit.  That bad decision is compounded by the fact that the system is low voltage (nominally +12 VDC), which means that a lot of current is involved to get the power to move the windows.  The large currents eat the control switch contacts -- burns them up.  Then the whole concept of using the door hinges as the connection back to chassis ground is collasaly stupid, given what's known to happen with age and wear.  Add to that the normal aging process in a 26-36 year old car with grease and lubrication getting dried out and stiff and it's a wonder ANY of them work.  I used to design circuits for a living and I can tell you that had I designed anything that poorly I wouldn't have lasted the 25 years I spent in the industry.  Randy's right -- if you're going to pull it apart, fix it right the FIRST time.

[bad76]

The relay set up is definitly the way to go. I have done it also but i would just buy a four relay board and that would make the install easier. The relays keep the heavier load off of the switch and in a dc circuit bad contacts can cause burnt up solinoids. The relays have much larger contacts and when you use your switch for switching the (negative) ground on the relays you put the lighter load on the switch. Damn it Rick, your post came up as i was wrighting this and you said it better. I agree 100%    

[brian c]

Yep I'm in the process of doing the conversion right now. Bought 3 of 4 relays at Radio Shack along with some terminals. Cost so far is $35. Need to get one more relay - I bought all they had in the one store - on the way home tomorrow. Made a metal bracket from an old computer case to mount everything to and it will also provide a nice grounding spot. I'll post some pics once I get everything squared away and installed. I do like installing it under the center console - between map pocket and shifter. Hope I have enough room there with the stereo I have...we'll see!

[brian c]

Here it is on my desk...





Bolts going through the relays....#8 x 1/2" with #8 washers, #8 lockwasher (backside) and #8 nut (backside)

Red wire is 10g which will be fused and fed with 8 gauge wire directly from the battery using a distribution block from KnuKonceptz. Feeding the distribution block will be a 4 gauge wire from KnuKonceptz as well. The other side of the distribution block will feed the Pioneer amp in the trunk.

Green wire is a common ground which will run to a good chassis ground - probably at the shifter.

White and black wires will feed to/from the power window harness as needed.

Now just to install it

[Wallington]

I just got mine rewired as per diagram, thanks guys! Will shoot a few pics up here when I get the car back in a few days time. The relays have been fitted behind the glovebox area.
Ben

[pstein]

Sorry, this might sound dumb, but would this make my windows roll up faster?  I might post a new topic for this...

[78ta]

No need to post up a new question.
Yep, that's the main reason for rewiring the circuit using the relays. A side benefit is taking the large amount amount of current load off of the power window switch so the contacts inside of it don't burn up.

There are few basic reasons for slow power windows.....

1. Sticky or dirty window regulators. The grease may harden up over the years.

2. Slow/Bad power window motor. May be for the same reason as above regarding the grease hardening inside the motor or could just a bad 30 year old motor.

3. Poor ground return for the power window motor. There is no actual ground wire from the motor to ground in the factory design. The factory design relies on the physical connection of the window motor housing to the door, the door to the door hinge and the door hinge to the chassis/body of the car. Any type of corrosion in any of those connections will hinder the ground path for the motor reducing motor performance.  So adding a ground wire directly from a mounting screw for the motor to a known good grounding point on the body pretty much guarantees a good ground for the motor.

4. There could be a voltage loss occuring at(within) the circuit breaker. I understand that the windows didn't work great with a solid 12-14 volts when new so if you have a voltage drop at the circuit breaker, you may now only have 10 or so volts powering the circuit. This will cause the motors to run slow, if at all.

5. The factory design runs _ALL_ of the current for the window motors through the power window switch. So if you have a poor ground path for the motor, the motor will draw more current than normal to move the window. The excessive current flow through the switch contacts will cause the power window switch contacts to be pitted and have carbon build up causing yet more resistance and more current draw.

There may be other reasons but I think those are the biggies.

[brian c]

Just a small update on my install....ended up going with this kit instead to provide the 12+ to the relays and also power my amp in the trunk...

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=19122

I'll do 4g to the distribution block which is fused, then one 8g leg will feed the amp while the other 8g leg will feed the power windows. Leaves me enough 4g for future upgrades...subwoofer anyone?

[Wallington]

Mounting inside the console would have been neater and easier to access but the electrician I had working on my car didn't have the console and so came up with this instead. This is directly behind the glovebox, mounted onto the firewall top. Also note that this is a RHD car so this is basically where your steering column would normally be.
One other problem I had to adjust was that with new motors, the windows operate so fast and hit the lower bump stops a lot harder than before, there is a lot of flex in the door shell sheetmetal. After having one window nearly jam under the felt guides, I had to adjust the bump stop a little higher so the relays cut the power just as the glass disappears below the seals.
Thanks guys, another thumbs up for the wiring diagram!