87 325i Multiple Electrical Issues - BMW Forum

Racing325 · 09-24-2012, 08:06 PM

Hey Guys , been a while since I been on here. I recently added an 87 325i to my collection of vehicles. I have been slowly fixing all the issues , but one has me stumped. So here are the 2 issues I currently have.

1. No continuity from the fuel pump relay to the fuel pump connector. I checked the resistance of the wire and it read 29.74K Ohms. I was wondering what the normal reading for this wire should be. Worst comes to worst I will just run a new wire from the relay to the connector.

2. When i turn the headlights on the dash illumination does not work , this includes the gauge illumination , the radio illumination , the clock/data center illumination and the heater control illumination. Does not work and the Odometer doe not work. I was wondering if there is a common ground for all of these.

Thanks in advance for any help. just trying to get this car so I can drive it full time.

Racing325 · 09-25-2012, 11:28 AM

Forgot to mention, the fuel pump issue started after i took the rear sear out to vacuum, not sure if the wiring for the pump runs around there at all

Lord Vader · 09-25-2012, 07:07 PM

The fuel pump is under the rear seats. Check the area to see if you disturbed something while vacuuming.

Racing325 · 09-25-2012, 08:03 PM

Got that issue solved, the power wire for the pump had been chewed and corroded. When I vacuumed it knocked the corrosion loose. Still need to solve the cluster issue.

Lord Vader · 09-25-2012, 10:47 PM

Their should be a common ground. Only way to know what the issue is, is to remove the cluster. The cluster contains numerous little bulbs.

Racing325 · 09-26-2012, 05:52 AM

I know about all the little bulbs, but found it highly unlikely that they all went/are missing, appreciate all the help you are giving, I am an ASE Master Tech but this is my first BMW I have really dug into and I know nothing about them, and am finding it hard to find wiring diagrams for them, so my first thought was to ask guys that have been doing this alot more than I have.

deafdog · 09-26-2012, 12:31 PM

Inside your dash is a PC board that has 2 AA rechargeable batteries soldered to the board. I would replace those batteries, they tend to go bad after a few years. If your 325i is like my 87 325 the PC board is right behind the oil/service indicator lights, you have to remove the cluster to get to it. My dad sent his to a guy that rebuilds them for under $100 because his corroded and leaked all over the board. I can find out who his tech was if your board is destroyed.

My dash lights are really dim in general, even with the rheostat all the way up.

Racing325 · 10-26-2012, 12:19 AM

Well I got almost all of my issues figured out. What I found with the illumination was that the headlight switch was bad , pulled the one out of my 325 and all the lights work now. I took apart the cluster and the odometer drive gears were toast. Got ne wones from pelican and it still does not work. can spin it all by hand and it works fine , but now when i actually drive. any suggestions.

also figured out a power window issue i had. been plucking away at this one issue at a time,

m20enginebuilder · 10-30-2012, 01:39 AM

Quote:

Originally Posted by Racing325

Well I got almost all of my issues figured out. What I found with the illumination was that the headlight switch was bad , pulled the one out of my 325 and all the lights work now. I took apart the cluster and the odometer drive gears were toast. Got ne wones from pelican and it still does not work. can spin it all by hand and it works fine , but now when i actually drive. any suggestions.

also figured out a power window issue i had. been plucking away at this one issue at a time,

Is your cluster entirely electronic? If so, theres a little motor that runs the odometer numbers, and if its burnt up, it wont actuate the numbers so they will not change. So possibly, your odometer motor may be toast.