Power Door Lock Troubleshooting.

[commando1]

1976 NYB 4 dr. w/this style switch pad in driver's door.
The gang of 4 is for the power windows.
Problem: This master switch no longer works on driver's door.
All other doors lock and unlock, both from this panel and at their individual switches.
Ths alone tells me the driver's door lock actuator is NG.
But....

When flipping the driver's door power door lock master switch several times rapidly, the power door lock relay for all the doors cuts out.

Bad driver's door actuator overloading the relay?
or...
Bad relay affecting driver's door actuator?
or...
Driver's door actuator AND power door lock relay bad?

I'm looking at the wiring diagram and it's not making sense.

 

[crackedback]

Sounds reasonable that the actuator is out of commission if the other locks activate from the Dr door switch. Could also be a wiring issue from switch to actuator.

Any way to easily hot the actuator. I think those are a reversing polarity style actuator.

 

[Big_John]

Any chance you can post a wiring diagram? I have an idea what's going on... I think it's the relay.

 

[commando1]

Any chance you can post a wiring diagram? I have an idea what's going on... I think it's the relay.

Yes. I'll scan it and post it up here tomorrow.
Thanks.

 

[cantflip]

1976 NYB 4 dr.
Problem: This master switch no longer works on driver's door.
All other doors lock and unlock, both from this panel and at their individual switches.
Ths alone tells me the driver's door lock actuator is NG.
But....

When flipping the driver's door power door lock master switch several times rapidly, the power door lock relay for all the doors cuts out.

Bad driver's door actuator overloading the relay?
or...
Bad relay affecting driver's door actuator?
or...
Driver's door actuator AND power door lock relay bad?

I'm looking at the wiring diagram and it's not making sense.

Ok... I'm looking at my recently acquired 1978 wiring diagram... may have difference, shouldn't be a big deal.

First your symptom of all other actuators work... problem is driver door circuit ONLY... there is one relay set if any work, relay works.

Second follow your power source to the fuse block... circuit W5 14 gauge Red wire... 30 amp circuit breaker... position 10... cycling the locks is opening the breaker, which cools and resets after a moment. May indicate your failed circuit is low resistance/shorted or that your breaker is getting weak... not conclusive, but the same breaker provides power to the seat motors... if they work good, its not the breaker getting weak.

If you find the seats work good, eliminating the breaker... you have most likely proven a low resistance/shorted lock solenoid. Because a wire would tend to "dead short" and open the breaker immediately. To further verify this, you could ohm the solenoid (driver's door is hard wired, panel removal required) and compare it to a rear solenoid which have a connector in the right rear sill plate area (wont have to remove door panel).

From what I know of you Stan, there is a chance you have a spare actuator. That would eliminate the need to compare to the rear and allow a quick plug in verification.

There is one other possibility, you may have a jammed lock mechanism... but my wiring shows the actuator as a solenoid... that could only cause the problem if it was a reversible motor.

 

[cantflip]

Addendum... The same breaker also supplies the windows...

 

[1978 NYB]

Stan....

1. I had the driver door lock button jam once on my NYB. Unscrew it and take off completely. It's a longshot.....

2. Do you have another driver door switch pad? Swap it for a quick check. Can be done without taking the door panel off. But you knew that....LOL!

3. Give Ross the multimeter and tell him to get hot! LOL!

 

[commando1]

Catnip may be on to something because I have a lazy power seat.
Im gonna try that relay kit that somebody just posted a week or so ago.
Then I'll go with the actuator if nec.
Then finally, the master PDL switch.
Thanks guys. Now I have to find the post with the kit in it.

 

[cantflip]

Catnip may be on to something because I have a lazy power seat.
Im gonna try that relay kit that somebody just posted a week or so ago.
Then I'll go with the actuator if nec.
Then finally, the master PDL switch.
Thanks guys. Now I have to find the post with the kit in it.

PM sent...

 

[78Brougham]

It's the thermostat! LOL... I think its in the master switch.... take it out and clean it. By thrusting it back and forth like you said, its making contact intermittently, and only works when agitated appropriately.