Power locks and interior lights

I have an issue that has me baffled. The interior lights and power door locks sometimes stop working on my 97 Riviera. I have an aftermarket alarm system and neither the key fob or interior buttons will activate the locks, and the interior lights won't come on. The dash is still fully illuminated, just the dome and door lights. I've checked the fuses, and they are fine. When this happens the beeping that lets you know the keys are in the ignition also doesn't sound if that is relevant to this issue. It happens randomly, then will go away after awhile.

Have you checked inside the flexible couplings between the body and doors. The wires running inside can break creating all kinds of symptoms. So can bad grounds.

moestippich wrote:

I have an issue that has me baffled. The interior lights and power door locks sometimes stop working on my 97 Riviera. I have an aftermarket alarm system and neither the key fob or interior buttons will activate the locks, and the interior lights won't come on. The dash is still fully illuminated,  just the dome and door lights. I've checked the fuses, and they are fine. When this happens the beeping that lets you know the keys are in the ignition also doesn't sound if that is relevant to this issue. It happens randomly, then will go away after awhile.

Your alarm system *may* be the problem, Rivieras defy electrical mods (I will spare you the explanation).

However

My guess is it's either the door switch is failing, or the wire bundle that goes through the door jamb is frayed and shorting to the car body.

The door switch is embedded in the door latch, to fix it you have to replace the latch. I have replaced both of mine at some point.

The door jamb wires can be re-wrapped with tape if they are not frayed too bad, just don't short them to each other.

Thanks for the info. I'm suspecting the wires since there was a problem before the alarm was installed. The locks didn't work at all when I got the car, and I took it to a shop for repairs. Had to go back a few times for them to go over what they did. After the last time everything started working a few days AFTER. Needless to say they probably didn't have a shop manual and were probably just going off general knowledge. I ordered the 2 book manual which should be here Monday. I'll take some time this weekend to look over the wires and see if I can spot anything. Already changed the door latch last year, so I doubt if that's the issue since the dome lights are involved as well. I'll report any updates as they occur.

moestippich wrote:

Thanks for the info. I'm suspecting the wires since there was a problem before the alarm was installed. The locks didn't work at all when I got the car, and I took it to a shop for repairs. Had to go back a few times for them to go over what they did. After the last time everything started working a few days AFTER. Needless to say they probably didn't have a shop manual and were probably just going off general knowledge. I ordered the 2 book manual which should be here Monday. I'll take some time this weekend to look over the wires and see if I can spot anything. Already changed the door latch last year, so I doubt if that's the issue since the dome lights are involved as well. I'll report any updates as they occur.

Working on Riv electricals without the schematics in the manual is deadly. They work but they do not necessarily work as you might expect.

Did you change the door latch for new or used? IF used you might have got a mechanically good latch with bummed electrics.

The latch was a junkyard part. I could just t4y to grab another one to see what that does. But would it also effect the interior lights not working. They happen simultaneously. A shame that I just left the junkyard getting another wiring clip for the O2 sensor.

Tried 3 different latch assemblies while it was out, and neither one of them fixed the problem. All the latches can't be bad, so I'm going to rule that out. I ordered the repair manual last week, and it is due to arrive tomorrow. I will try looking over the schematics to see if I can figure something out, but I have no idea what I'm doing here. Hopefully my ability to learn these type of things very quickly pays off, and I won't have to go to another shop and fork over money that I can't afford to spend on such a minor issue. It's only the power locks and dome lights (the alarm still works when the situation occurs) and I just have to let myself in with the key. But it annoys me knowing there's a problem, and I want to fix it.

If my aftermarket alarm is the culprit, what would be a solution. Am I looking for substandard installation, or could the alarm system itself be causing the problem. It's a pretty simple alarm (Silencer SL-42) with a 2 way pager key fob, and the shop that installed it has a great reputation. I also had problems with the locks not working at all BEFORE the system was installed. That was taken care of by a shop who, in my opinion, USED to have a good reputation, but since the old man who owned it retired they are coasting off of the name of the shop staying the same.

Reading through the repair manuals I just got today. One thing that stood out was the reference to testing the Body Control Module. Curious te see how much it would be to replace the BCM, I did a quick search for one. It looks just like the HVAC Programmer box that I had to replace with a junkyard part when I had a problem with my climate controls. Are these one in the same? If it is, then I can just go grab another one from the junkyard and see what that does.

This is it, http://www.rockauto.com/en/moreinfo.php?pk=86437&cc=1022050&jsn=400

93.79 at www.rockauto.com

moestippich wrote:

Tried 3 different latch assemblies while it was out, and neither one of them fixed the problem. All the latches can't be bad, so I'm going to rule that out. I ordered the repair manual last week, and it is due to arrive tomorrow. I will try looking over the schematics to see if I can figure something out,  but I have no idea what I'm doing here. Hopefully my ability to learn these type of things very quickly pays off, and I won't have to go to another shop and fork over money that I can't afford to spend on such a minor issue. It's only the power locks and dome lights (the alarm still works when the situation occurs) and I just have to let myself in with the key. But it annoys me knowing there's a problem, and I want to fix it.

Actually, all the latches could be bad. The door latch switch is in a "hostile" environment, basically there is a microswitch in the latch and I was told that the contacts corrode with age but generally don't fail within the car's warranty period. My thinking is they should have used milspec instead of commercial switches for that application but i do not have direct knowledge, have not torn a latch apart to see the switch.

I imagine one could test the switch with a meter but I am not sure how.

I replaced each of my latches several years ago with new, as they failed, and have not had a problem since.

One way to test the actuators I have is to swap them out at a time when mine are working. Or see if the entrance ligting even goes out when I unplug it. If everything goes out when I put the other one in that would confirm it. If the lighting stays on that would rule this out. I'll do some more tinkering this weekend to see what I come up with.