: Twilight Sentinel Behavior and Odd Interior Light Issue

08-03-11, 10:08 PM
All this relates to my '94 Fleetwood....

First, with the Twilight Sentinel in any position other than "OFF", the headlights come on as soon as I turn the ignition to run (when it's dark out, of course). My '96 only turned on the headlights once I put the car in drive. Is this difference simply a change in the model years?

Second, I have an interesting issue with the interior courtesy lamps. Since it's a limo with a partition, the interior lighting is split between the front and back. If you open either front door, only the front roof rail courtesy lights turn on. When you open 3 of the 4 rear doors, the rear roof rail courtesy lights come on. The exception is the right rear door. When I open it, none of the lights come on. BUT, the "DOOR AJAR" light illuminates on the dash. So the car knows the door has opened. Even stranger, when you try to turn that right rear roof rail light on manually (by pushing it), it won't turn on. But open any other door on the car and that light lights up. Anyone ever seen that happen?

08-03-11, 10:27 PM
Jimmy the 96 had daytime running lights standard
94 only on export
the sentinel most likely the sensor in the dash vent
theres 2 one is the sunload sensor (blue dome)
the other is the l/s may have fallen down into the dash
check that I have the photo diodes if yours is no good
the rear courtesy light turns on by grounding so I would take it down and trace the ground wire from that switch, im sure its the mini wedge
in the lock mechanism causing it to not light up when opened
I will be putting together your parts request in the next day or so.....Jimbo

08-03-11, 10:57 PM
Thanks for that. My '96 didn't have DRLs - the limo option removes it. But I would bet that this is the difference in behavior.

I should have mentioned that the door courtesy lamp on the right rear door doesn't work either. This one is tougher to diagnose because the coach builder split the light system between front and back. I think you're right tho - gotta be a ground thing.

Lookin forward to having the AC work....:)

08-04-11, 12:00 AM
It sounds like your 96 did have them because that's how GM usually did it by turning them on when you take the car out of park. If it really was turning on the headlights that is probably something the coachbuilder did for some reason.

08-04-11, 11:36 AM
It sounds like your 96 did have them because that's how GM usually did it by turning them on when you take the car out of park. If it really was turning on the headlights that is probably something the coachbuilder did for some reason.

My '96 didn't even have the DRL module or the RPO for DRLs. I guess they eliminate it with the V4U (like the traction control and ABS). My guess is that the Twilight Sentinel behaved sort of like the DRLs since the lights only came on when it was in gear (and dark, of course). What was odd, too, was that I couldn't shut the lights off once they came on. If I slid the Twilight Sentinel switch all the way to "OFF" with the key on, the lights would stay on. I'd have to shut the key off before the lights went off. All DRL-like behavior, but I know for a fact there was no module for them.

The '94 lights come on when I start the car (when it's dark now that I goofed around with the photoresistor) AND I can shut the lights off by sliding the switch to "OFF".

On the right rear door switch.....could it be the mini-wedge switch even if the dash is saying "DOOR AJAR" when the door is open? So the dash is somehow aware, but the interior lights aren't coming on. I was able to get the roof rail light above that door to come on manually (with the switch) after goofing around with it.

I'm wondering if the right rear door courtesy lamp has anything to do with it. All the lights in the car come on with any of the other 3 doors EXCEPT that courtesy lamp on the right rear door. I swapped the bulb and it still doesn't work.

This limo is a bit more challenging to diagnose because the audio and lighting is split between the front and rear. I don't even know if they use the central control module for the rear, or for anything for that matter.

I've got much bigger fish to fry, but it's the little things that bug me....

08-04-11, 06:22 PM
Fixed it. The connector for the mini-wedge switch was corroded and a single wire had broken off. Apparently this wire was for interior illumination while some other wire that didn't break lights up the "DOOR AJAR" message on the dash.


The door courtesy lamp still doesn't work though. There's no voltage to it for some reason. That's a project for another day.

08-05-11, 11:39 AM
One little glitch down , one to go then :)

08-05-11, 04:36 PM
One little glitch down , one to go then :)

Yep. And it's going to bug the crap out of me until I figure it out. I want to put all LED interior lights in it like I did with my '96 so I gotta get that one courtesy lamp working.

08-08-11, 11:43 AM
LEDs are just cool that was I would recommend you , makes a huge difference compared to dull lamps lol