Help! my new instrument cluster

[vtman05]

Well I finally get around to getting another known working cluster. I install it and everything is great....for about 5 minutes :( My instrument backlights go out and my tach dies... WTF I do all the routine checks on the fuses and what knot and everything is good to go. AND the temp gauge works so the SI board batteries are good. BUT I don't have any dummy lights on. Anyone have any ideas on what could have knocked out the tach just like that?????


Thanks

I think the new radio I installed my be shorting out my dimmer switch. Going to check it out.

While fixing this stuff I checked power to the fuses with a test light and found that 21 - 28 have constant voltage with the car off. Is that right?

[vtman05]

While fixing this stuff I checked power to the fuses with a test light and found that 21 - 28 have constant voltage with the car off. Is that right?

[vtman05]

hey thanks for chiming in matt,

I don't think I have the dimmer wired into anything. It is just heat wrapped. The wires not hooked up are the fade dimmer light and a radom white wire that looks to be looped in the dash.

I have another working si board. I will give it a go and see if that changes anything.

Link to my cars fuse descriptions

http://www.wedophones.com/Manuals/BMW/1988%20BMW%20325i%20Convertible%20Electrical%20Troubleshooting%20Manual.pdf

page 12 has a list of all the fuses. The fuses are fine and I have a current drain of < 70mA on 21.

I do have a battery drain problem if I don't use the car everyday. I am in the process of chasing down the drain.. so far not the glove box or radio.

[AndrewBird]

70mA is virtually nothing. It's probaly just the clock on the radio and the OBC drawing that.

Fuses 21-28 are supposed to have power to them all the time. They power things that are on constantly like the parking lights, glove box flashlight, dome light, etc... They are all switched by some switch somewhere, but don't need the ignition on to power them.

As far as your cluster goes, I have no idea.

[vtman05]

Thanks nitro, after talking with a buddy yesterday we came to the same conclusions. I tore into the cluster and replaced the si board and tested all the bulbs. I am going to install the cluster again and see if this changes anything tonight.

[vtman05]

well i got the lights all up and going. Turns out the backlight bulb works but doesn't work with the board. So I think I may have some minor cracks. The good thing is the car is up and running and I am pumped.