Instrument Cluster / Wiper problems

[Steveclaire]

Hi, I wonder if someone might be able to shed some light on an (apparent) electrical problem I have with my 1990 525sei (M20).

The speedo occasionally stops working. When this happens the wipers at normal speed setting will only work intermittently and the engine fails to rev over 3000rpm without severe misfiring.

When the speedo starts working again, the engine is fine and the wipers work correclty. Searching on other forums, I notice reference to a motion / speed sensor for the wipers - designed to make the wipers work intermittenly when the car is at rest (apparently this design is common to all E34 models?))

I've had the back seat up, and notice the power distribution board and wiper control unit, but beyond that, I'm not sure what I should do.

Any help in resolving this matter would be greatly appreciated.

Thanks

[bsell]

Hi, I wonder if someone might be able to shed some light on an (apparent) electrical problem I have with my 1990 525sei (M20).

The speedo occasionally stops working. When this happens the wipers at normal speed setting will only work intermittently and the engine fails to rev over 3000rpm without severe misfiring.

When the speedo starts working again, the engine is fine and the wipers work correclty. Searching on other forums, I notice reference to a motion / speed sensor for the wipers - designed to make the wipers work intermittenly when the car is at rest (apparently this design is common to all E34 models?))

I've had the back seat up, and notice the power distribution board and wiper control unit, but beyond that, I'm not sure what I should do.

Any help in resolving this matter would be greatly appreciated.

Thanks

With so many different things happening at once, I wonder if a grounding point has come loose... Grab your electrical manual and chase down all of the grounding points associated with your troublesome systems. Clean the junctions and re-tighten.

If that doesn't do the trick, check the connectors for these systems. I've seen a major connector disconnect and create symptoms like yours. The trouble is finding the offending connector...

Brian

[gtopaul]

Hi, I wonder if someone might be able to shed some light on an (apparent) electrical problem I have with my 1990 525sei (M20).

The speedo occasionally stops working. When this happens the wipers at normal speed setting will only work intermittently and the engine fails to rev over 3000rpm without severe misfiring.

When the speedo starts working again, the engine is fine and the wipers work correclty. Searching on other forums, I notice reference to a motion / speed sensor for the wipers - designed to make the wipers work intermittenly when the car is at rest (apparently this design is common to all E34 models?))

I've had the back seat up, and notice the power distribution board and wiper control unit, but beyond that, I'm not sure what I should do.

Any help in resolving this matter would be greatly appreciated.

Thanks

Start with the basics. Check your battery and alternator to make sure they're not the problem.

Paul

[E34-520iSE]

I reckon the speed sensor on the diff is dead/dirty/falling asleep. The signal it generates goes to various control units. You will notice that when your car is cold and you allow it to roll forwards, the idle speed increases. At a standstill the wipers are on intermittent wipe until the car start's to move, and (obviously) the speedo begins to register when the car is moving. That sensor is very important - check it out!

HTH,

Shaun M

[Claude]

Hi, I wonder if someone might be able to shed some light on an (apparent) electrical problem I have with my 1990 525sei (M20).

The speedo occasionally stops working. When this happens the wipers at normal speed setting will only work intermittently and the engine fails to rev over 3000rpm without severe misfiring.

When the speedo starts working again, the engine is fine and the wipers work correclty. Searching on other forums, I notice reference to a motion / speed sensor for the wipers - designed to make the wipers work intermittenly when the car is at rest (apparently this design is common to all E34 models?))

I've had the back seat up, and notice the power distribution board and wiper control unit, but beyond that, I'm not sure what I should do.

Any help in resolving this matter would be greatly appreciated.

Thanks

I experienced same wiper reaction when my cluster got intermittent (no speed, no rpm, no fuel level indication) it never happen again after i solve my cluster problem (just replace it by a recondition one), reason why : the wiper control take the car speed information from the cluster. You notice that when your cluster readouts are ok your wiper problem disappears. So don't loose your time seaching elsewhere the problem source you've already pinpoint it : your cluster intermittence.

I did'nt experience engine fails like your's when my cluster was intermittent, i can't relate the two things, perhaps others can.

Good luck.

[patznu]

These issues may all be seperate and have no relation. I also had similar problem, me , I replaced cluster and along with plugs and wire..done with issue. After checking the basics, you may want to try disconnecting cluster, the start the car to eliminate one of three issues, maybe. I wish you well !!