1989 525i brake light issues, and

Hi, I have a 1989 bmw 525i ... I have problems with the entire insterment cluster going dead when I push the break pedal... it only seems to happen when the car is cold. It also seems to be affectied by the high brake light in the center of the rear trunk by the rear window. If I pull the bulb it seems to help, and sometimes it does not... if I pull the bulb, I do get the message " 1 brake light out. but when the car is cold, or not been started for awhile, it still flakes out.When it flakes out, the oil gauge and fuel gauge are also effected, It sometimes is intermitent, and some times all is ok... provided I do not press brake pedal when car has been sitting for awhile. All the symptoms happen only when brake pedal is puished I have some experience at electrical and have the wiring diagram. Also, when warm, if I turn the head lights on.. when pressing the brake pedal, the insterment cluster dims,, Is it possible that the lamp control module needs to warm before everything is ok, would it flake out when the car is cold, or not been run, started and warmed up ?

I have the same car - 1989 525i, with a similar problem. All the dials except for the speedo and tach are dead. I'm told it's a problem with old capacitors on the power supply board inside the cluster. I took it apart to see if I could fix it myself, I'll let you know what I find out. The cluster is really easy to pull - just take out the two little screws at the top, pull the steering all the way out, wiggle the cluster out a bit, use the little levers to pop the four plugs out. Here's some great sites:

formatting link

I'd suspect that cold is the major contributor - capacitors age and fail a little like batteries do. When you have a large draw, like the headlights, they can't keep the voltage up, and then the dials won't work. I did find out that we can swap clusters with other early 5's and 7's. The harnesses were changed around Feb 1989, so you might have an old one or a new one. Mine has a gray back, the newer ones are white, then they went to light blue. I don't know if the white ones work - the light blue ones certainly won't.