Instrument Cluster and Trip Computer failure

[G4DARE]

I have a 88 735i and the Temp gauge, fuel gauge, and OBC have shut off upon start up leaving work one day. I took a look at fuse #17 and found it to be blown. I replaced the fuse and started the car back up and it worked again. Shortly after turning the car off and restarting they failed again. I went out to the fuse box and found a different fuse (still instrument panel related- cant remember fuse #) to be blown. I replaced the blown fuse and now it still wont work. I haven't had the time to check for any shorts just yet.

Is this still an instrument cluster capacitor failure?

[unity]

I would doubt a cap failure would cause this. You could rule things out by pulling the cluster and disconnecting everything, then reconnecting each connection until a fuse goes. Then its a matter of knowing what that connector could be feeding on the cluster. Warning though, you will get an SRS light if you pull the cluster and turn on the car.

Maybe Shogun knows more about this issue.

[G4DARE]

That would be a good test to run. I would like to avoid removing the instrument cluster if I can avoid it but this could be a good first step to take.

[shogun]

Check here in the ETM for what fuse 17 is and the other blown fuse, select the correct ETM, from about page 14 all fuses are listed and for what they are http://shark.armchair.mb.ca/~dave/BMW/e32/
If 1 fuse is for various items, disconnect one after the other.
Performing Closed Current Draw Test
• Select proper measuring device (DISplus, MoDic or DVOM)
-Remember amperage draw in excess of 10A will damage DVOM.
-Use inductive amp probe of DISplus when amperage draw is high.
-When using DISplus inductive probe, clamp on negative battery cable witharrow pointing away from battery. Switch off all consumers.
-(It is not necessary to disconnect B- from body when using inductive probe)
• Connect (-) test lead to negative battery terminal and (+) test lead to a known good ground.
• Ensure all systems are OFF !
• Be sure DVOM is on and set in proper mode.
• Disconnect battery ground lead from body.
• Observe meter reading, wait for vehicle to enter sleep mode.
• Identify faulty circuit by disconnecting fuses, relays, control modules or connectors, observing meter readings.
• Defective circuit is found when current is below maximum closed current for vehicle being tested.

use this link for more details http://www.e38.org/battery.pdf

[G4DARE]

Appreciate the fast reply Shogun! I will be running through those tests this weekend to see what ends up being the issue. Ill post up once completed.

[G4DARE]

Just from a quick look at fuse #17 on the ETM its looking like that's my problem. My power locks aren't working neither is just about everything that fuse #17 describes. Could it be a faulty GM that's straining and blowing the fuse? Fuse #17 also includes the GM

[shogun]

Fuse 17 is for many things if you look at the ETM. But as your power locks are not working, that is a good starting point. First I would check if the wire loom is broken between A-pillar and door. At the bottom there is this rubber piece which is held by 2 bolts, If you unbolt these, you can pull back the rubber and see the many wires inside.
It must be a short somewhere, not a non functioning GM.
Also check the GM area if there is water from a blocked sunroof drain hose.

[G4DARE]

Your definitely right there is a short somewhere. I just had a little set back with my alternator/ fan belt. I believe the top pulley is bad and keeps breaking my belts. Anyway I once I have that sorted I will be able to take a look into the wire loom as mentioned and let you know of my findings.