1987 BMW 325 blown fuse #10. Instrument cluster gauges inop

Tiny
BRALDEN
  • MEMBER
  • 1987 BMW 325
  • 6 CYL
  • 2WD
  • MANUAL
  • 130,000 MILES
Hi. The car runs fine but blows fuse #10 every time the key is turned to the on position. I have a continuity tester and hooked it up to both sides of the fuse. I found a short in to ground(chassis) on the reverse lighting circuit where the wires go from the right side of the transmission(reverse light switch) up through the shifter boot and continues back under the carpet to the reverse lights. What a design flaw. I have that repaired and disconected now and STILL have a short. The HVAC blower motor is evidently on the same circuit because it will come on momentarily. I shut the switch off and it still will blow. What else can I disconect or try? Any help is greatly appreciated.
Do you
have the same problem?
Yes
No
Monday, September 13th, 2010 AT 2:32 PM

8 Replies

Tiny
DR. HAGERTY
  • MEMBER
Relay K7 and the active check control module are on fuse 10 as well as the instrument cluster. Relay 1 is top left, 2 is next to it as so on. The first thing to try is to take the check control module out of the circuit, it is the square lighted thing that you look up to see by the rear view mirror, if that aint it, remove the wires to the back up light switch and recheck for fault to ground. Then the only thing is the instrument cluster.
Was this
answer
helpful?
Yes
No
Monday, September 13th, 2010 AT 6:19 PM
Tiny
BRALDEN
  • MEMBER
I removed the check control module from the circuit by the rear view mirror. Still no let up. The radio and instrument cluster are now removed, the back up lights are removed from the circuit and I checked the two wires for a short to ground and to themselves. Thank you for your prompt reply. It is a convertible if that helps. I know they can leak.
Was this
answer
helpful?
Yes
No
Monday, September 13th, 2010 AT 7:49 PM
Tiny
DR. HAGERTY
  • MEMBER
What was the outcome of your work, you did not state it.
Was this
answer
helpful?
Yes
No
Tuesday, September 14th, 2010 AT 8:09 AM
Tiny
BRALDEN
  • MEMBER
Sorry. Let me explain. The short still exists even though everything that I have mentioned is completely disconnected except for the blower motor. I only turned the switch to the off position. Also I want to correct a statement: I did get a ground reading from the green white wire from the back up light circuit. The ground is not coming from the back up light switch itself but the green/white wire going to it. This I suspect is normal. I still have the sensor disconnected along with everything else untill I find the short. Again the IC, the reverse light connector by the shifter, the overhead control module(by the center rear view mirror and cabin light) and the radio are fully disconnected but I still have a dead short on fuse 10. What else can I try?
Was this
answer
helpful?
Yes
No
Wednesday, September 15th, 2010 AT 12:53 PM
Tiny
DR. HAGERTY
  • MEMBER
The short to ground is not normal. Disconnect that wire and find the short.
Was this
answer
helpful?
Yes
No
Wednesday, September 15th, 2010 AT 9:10 PM
Tiny
BRALDEN
  • MEMBER
Wow. Ok I will look for that short on the back up light ckt first thing tomorrow and report back to you. Thanks for the help.
May I ask what wiring diagrams you use? I do have All Data, On Demand(the Michelle program), and a GT1 at my disposal from friends of mine.
Was this
answer
helpful?
Yes
No
Thursday, September 16th, 2010 AT 9:58 PM
Tiny
BRALDEN
  • MEMBER
Ok. I've taken the drivers seat, the center console and some panels out. I also raised the carpet on the drivers side and unraveled all of the tape to trace the wire where it connected to 7 other wires, all green with a white stripe. One by one I cut the wires from the splice connector with my continuity tester on the ckt until the beeping stopped. I then followed that wire through the wiring harness, removed the left side drivers kick panel, and followed it to a relay. The number on it is 1 372 719. I called the dealer and the number is now changed to 61311372717. It is $60.00 plus tax! They said it was the Starting Contol Unit Saftey Belt (relay). Big name, BIG PRICE. It just looks like a long relay to me with numbers 31 and 15, letters, L and S on it. When I removed the relay, the short disappeared. I tried to test the relay by hooking up power and ground to it and checking for continuity. It clicked when voltage was applied to two of the poles but did not provide continuity on the other two poles. It looks like the relay, ohh sorry, the Starting Contol Unit Saftey Belt is bad........ 24hrs later. I meant to send the previous info. YES. It was the relay causing the short! Problem solved. Only thing is when I put it back together the windows did not work! I went through the diagrams I found on All Data and Michelle and took the IC back out and spent another hour and a half before I found the problem- a disconected connector completely out of sight in the wiring harness above the drivers left side kick panel. It was really hidden in there untill I pulled it out and reconnected it. Obviously it must of been disturbed while I was in there. Now everything works again. Only one other issue. The odometer and tripometer do not work. I replaced the batteries in the IC in the begining of all this but had the problem before I had replaced them and before the short. I will be investigating this problem now..... 5min later. I just looked it up and it looks like its caused by the plastic gears wearing out in the cluster. I already found a website that sells them- odometergears. Com. Thanks for all of your help. Good job. I really appreciate it. Is it ok to wire a tip to you?
Was this
answer
helpful?
Yes
No
Saturday, September 18th, 2010 AT 10:13 PM
Tiny
DR. HAGERTY
  • MEMBER
Thanks for the update. And you may donate to our site at your discretion, thanks for using 2CarPros!
Was this
answer
helpful?
Yes
No
Sunday, September 19th, 2010 AT 12:00 PM

Please login or register to post a reply.

Recommended Guides