1999 Suburban LT w/ electric locks that are having fits.
There are times that ALL of the locks cycle just fine. There are times that
the driver's door and the driver's side rear passenger door just do not work
at all then will work again. If you continue to cycle the locks, the front
passenger and rear passenger door locks only operate half way. Stop and wait
a few seconds and they will cycle just fine.
The REALLY strange thing, leave the dome light button set so they come on
when you open the doors and they may not turn off after the 10 second delay
when the doors are closed AND they may turn on very briefly when coming to a
stop or flash when hitting a bump while driving. Turn the button off and
they never flash, but of course they do not come on when the doors open
What I've tried to this point:
I thought maybe there was a loose connection in the driver's door so I
pulled the panel, checked all connections and the cycling of the solenoid
for that door. Everything looked good and operated as it should. No binding,
smooth operation when it worked, etc. Next I located the relay for the door
locks that is mounted to the left of the center heater duct under the dash.
This is the six terminal relay. Pulled it and the dome lights operated as
they should after the doors are closed by going off after about a 10 second
delay. I thought, OK it's gotta be that relay causing the grief. Replaced it
since it doesn't cost much and the SAME things continued to happen!!!
1. I could hear another relay (?) clicking somewhere even with the black six
terminal relay removed when pressing the lock button in the lock position.
Is there another relay somewhere under the dash?
2. If one of the lock solenoids is weak, will it affect the others this way?
All cycle smooth and then start only half cycling or not at all?
3. Suggestions of where to look???