308 Windows Dead Electrical

Seeking help to fix dead windows in my 1977 308 GTB (US Version). Much written in FChat about this and elsewhere. Thanks for the wiring diagrams, advice in other threads. I am out of ideas having worked on these windows' electrics for many, many hours. Probably time for a mechanic versed in this era of electric windows. Meanwhile, I have a few questions to see if I can to see this fix through.

First I confirm per above, a 1977 (October) US cara. Per Big Tex remark I read - 1976's and 77's were prototpyes! So what I describe is possibly not equal to all 77's but I think all 77's have two switches on driver armrest console, one for pass side window. One switch on pass armrest.

Note the windows worked well, with the pass side switch not working, then the driver window slowed to a crawl then dropped off completely. I dismantled the motor assembly and it was not gummed up at all. I cleaned it up though, and replaced the cable. This didn't help. Now I am not getting power at all, the whole system is dead.

So I am working on the electrics before I re-assemble the motor with new wire and re-install and set it up again.

I dismantled the driver's side switches both, one seems a replacement at some point but both now have clean contacts on the rockers and are generally clean.

I have tested the cleaned and re-assembled the drivers side driver window switch (and the drivers side pass switch) with the multimeter confirming continuity on the drivers side driver window switch as follows: with the drivers switch drivers window button forward, continuity from D (green wire to driver window motor) to C (striped - black stripe on white wire, to power supply), and also still with button forward, continuity between A (green to motor) to E (stripe to power).

I note the letters "E" and "F" above are for identifying the unmarked spades. These two E and F are the spades to the ground. (I.e. there are no small letters profiled next to those spades like there are in the case of spades A - D; but with spade B being the forward-most, I call F the un-marked spade for a wire to the chassis-ground/black that is across from B and I call E to the un-marked spade also for a wire to chassis/black across from most-rearward spade C.

With the switch button pressed back, there is continuity from A to B (motor and power supply, respectively) and continuity from D to F (motor and ground, respectively).

So in summary the switch causes continuity between the motor to power and the motor to ground, whether the button is forward or back. Per comments on other threads, I assume this is because the forward and back can switch the motor's polarity and direction.

So. Switch working, I believe. Fuse fine, I checked the relay with the multimeter and it seems fine - clicks when the coil is activated and continuity confirmed Image Unavailable, Please Login .

The motor works well when run direct from the car battery.

Questions:

1) Does the continuity tests results above seem right in the sense of which spades have continuity?

2) With ignition on, I sense no power when connecting a first MM lead to the wire(s) for power to motor (striped) and the second MM lead to the wire(s) for ground (black). Shouldn't there be a power reading on the MM, if connected to the power and the ground, if things are "working"? I note, until lately there was power to the windows, just not enough and/or the window and wires were not set well.

3) Note the ground is often said to be the culprit. I removed the ground wire lead from the inside of the door cavity bolt, where a nut tightens it to the door. I cleaned it and filed it to metal, etc. and cleaned the bolt and nut. No change. Also I ran the ground wire from its end that is normally fixed with to the inside of the door, direct to the negative post of the battery using a large copper wire length, just to ensure no issue with grounding. Still the switch when pressed forward or back, did not actuate the window motor.

4) Am I correct in assuming there is no communication between the switches themselves, i.e. there are wires from the general window motor circuit going to both, but no wires from one switch to the other?

5) I am seeing the circuit coming to the two driver's side switches as consisting of eight wires: one white (blk stripe) (gets split with both splits going to driver switch - power wires), one blue (blk stripe) goes to pass window switch (gets split both splits are power wires) two yellows (go to pass window switch and I believe these must come from the pass window switch located there and connect the two pass window switches) two greens (both go to drivers window switch for bringing power to motors ) two blacks, one to each switch that gets split and each split is a ground. So each switch has its own circuit feed wires from the circuit. Is this correct?

As I said I am running out of ideas, I note I didn't use a lead cleaner on the inside of the leads that fit over the spades but did ensure they were free of debris. Doubt dirty or corroded female leads are an issue. I avoided the ground issue by running the black ground wire normally connected to the inside car door, direct to the frame (negative battery post). Tested the switches, the motor. Hmm. Any ideas welcome!

 

Thanks very much Steve!

With the drivers window switch held on, there are 12V + - readings on the MM when touching the lead to the top and to the bottom of the correct fuse (second from right in left hand fuse box/row), second lead to ground. Will now chase the downstream culprits for a while further ... look for voltage drops I guess, starting at the window motor but any suggestions helpful!

Quick question no damage to anything by leaving the key "on" for sometimes 15 seconds ... (car had distributors converted to electronic ignition)? It is just that I have done that many times and now think its many more as I chase downstream-the-fuse (switch, probably) issues?

Neil

 

(This is Neil adding to my reply to Steve Magnusson, just above):

Further tests (all references to drivers side switch and motor):

1) I confirmed continuity through the two green wires (green wires convey power from switch to motor).

2) Motor test while connected to the switch. (Per above, the motor works or at least it works directly from the battery which I tested using a wire from each of pos and negative post to one of the motor's two terminals). For this test I first connected the motor to a sure ground to avoid any issue with the ground wire's continuity with the car frame which seems a common concern, by running a long heavy copper wire running to the battery negative post. Having done so there was no result - dead response- to turning the ignition to "on" and the switch "on" when running the green wires to the motor.

3) I tried to check whether there is continuity from the fuse/relay to the leads of the white with black stripe wire (ones conveying power from battery. (One wire from battery, splits into two leads) First, see above - there is confirmed power to the correct fuse and the relay is confirmed working. With ignition "on" I used MM voltage reading setting placing a probe in the lead of the first white wire lead unhooked from the switch, second probe to a sure ground. No continuity. Same, second white wire's unhooked lead. Is this a correct test for whether there is power continuity from the battery through the fuse/relay on to the leads going into the switch?

 

Neil Back to Steve - thanks again Steve for your help; will give further thought to it. Having tried the three tests noted just above and not seeing voltage from the wires that run from the fuse/relay to the switch ... thinking maybe that section is the place to focus on for now.

And thanks for your thoughts on key "on" harm or not.

Happy summer with your Ferrari(s)!

 

Exactly, with key and switch "on", I removed the BN wire from its switch spade, took red probe to the BN wire end and there was no reading at all. But on bottom of fuse with same "on", 12.3 or so volts. Is that definitive there is a broken wire from fuse or relay, to end of BN wire? Must be? (I am a total rookie).

 

Thanks for the suggestion. I did test the window motor via direct to + 12V battery and it worked well, seemed to spin hard, and pulled a cable from gloved hand etc. Your experience may be it. I did disassemble the switches, definately they were arcing on one of the three points per each of the rockers, cleaned those and the insides generally, and tested them - perhaps the test is misleading, as you say. As in, a connection but barely, isn't enough. Maybe need new switches even though meter found continuity?

 

This is really helpful Steve, giving it a go tomorrow when I am fresh and can think. What do you mean by a connector - do you mean the 6 wires running from out the behind-dashboard area through the gap and into the driver door? Or, do you mean the hinges (two) (or maybe the limiter-catch that limits how far the door can open)? I understand the negative current/circuit runs through the hinges (or limiter or all three). Maybe check to see if there is current between the male spade of the BN wire and one of those hinges?

 

Sorry should have said check to see if there is voltage, run another voltage check there.

 

OK, I'm clearer now. Will take a look. Just also noticed one of the wires has a tiny almost-invisible "nick" in it, from being pinched I assume. It isn't shorting (I'm doing the testing with the door open). But obviously needing repair. Thanks for hanging in there with the help, Steve!