Strange power issues?

[Danpatters583]

So, after putting off looking at the wire splices on my '90 Reatta for about a year, I finally decided to start the job. Ive been having alot of issues with my power locks, mirrors, interior lighting, trunk release ect. After scouring the forums it appears that this woukd be my problem. A Broken wire splice or two. I got to the splices and so far have checked about half of them and there is no corrosion or anything out of the ordinary. Im a bit confused since my fuses appear to be good. So my questions are as follows.

1) Is there something else I should look for? I saw something on on google about a power supply module? What does it do?

2) is it possible the body control module could cause all these problems? 

 

Thank you all for your help.

[Padgett]

Thee is a central power supply module but it mainly provides 7vdc for the instrument and not 12vdc for the items you mention. I'd put a 12v power monitor in the cigarette lighter and see if it jumps around.

Like this.

[Danpatters583]

I did happen to notice my instrument cluster is intermittent all of a sudden. I got multiple issues apparently. 

[Ronnie]

12 hours ago, Danpatters583 said:

Ive been having alot of issues with my power locks, mirrors, interior lighting, trunk release ect.

Are they not working at all or is this something that is intermittent?

[Danpatters583]

None of them work at all. Haven't since I bought the car. 

[Ronnie]

I would look at all those components not working as separate issues even though they all might be related.

 

Start with the interior lights. Do a little test to see if the problem is with no 12 volt power or with a ground. Interior lights are controlled by the BCM on the ground side of the light.

 

I'm assuming you have a coupe and I'm assuming your '90 is like my '88 model... Remove the cover from the overhead (dome) light so you can see the bulb. Use a meter or test light to check each side of the bulb for power. One side should have 12 volts. If it does, ground the other side of the bulb and see if the bulb comes on. If it doesn't, replace the bulb and repeat the test. Let us know what you find.

 

 

[Danpatters583]

On 4/20/2022 at 10:02 AM, Ronnie said:

I would look at all those components not working as separate issues even though they all might be related.

 

Start with the interior lights. Do a little test to see if the problem is with no 12 volt power or with a ground. Interior lights are controlled by the BCM on the ground side of the light.

 

I'm assuming you have a coupe and I'm assuming your '90 is like my '88 model... Remove the cover from the overhead (dome) light so you can see the bulb. Use a meter or test light to check each side of the bulb for power. One side should have 12 volts. If it does, ground the other side of the bulb and see if the bulb comes on. If it doesn't, replace the bulb and repeat the test. Let us know what you find.

 

 

It is set up like that. Ill check once I finish looking at the splices. 

 

Also, where is the bcm located? I haven't looked at the manual yet. 

[Ronnie]

The BCM is right behind the glovebox. Remove the glovebox and it will be the silver box with lots of wires going to it.

[Danpatters583]

9 hours ago, Ronnie said:

The BCM is right behind the glovebox. Remove the glovebox and it will be the silver box with lots of wires going to it.

Thank you. I'll let you know what I find. 

[Danpatters583]

On 4/20/2022 at 10:02 AM, Ronnie said:

I would look at all those components not working as separate issues even though they all might be related.

 

Start with the interior lights. Do a little test to see if the problem is with no 12 volt power or with a ground. Interior lights are controlled by the BCM on the ground side of the light.

 

I'm assuming you have a coupe and I'm assuming your '90 is like my '88 model... Remove the cover from the overhead (dome) light so you can see the bulb. Use a meter or test light to check each side of the bulb for power. One side should have 12 volts. If it does, ground the other side of the bulb and see if the bulb comes on. If it doesn't, replace the bulb and repeat the test. Let us know what you find.

 

 

So I tested the light bulb. Zero volts. New bulb is installed no difference. Ill dig a little further later. Boncing back and forth between a few different things right now.