cluster install

[e30construction]

ok well my new cluster is coming in today and i plan on putting it in..the guy i got it from says everything works and the si bats are good..can any1 tell me what the cluster does exactly when you turn the keys on so i can tell when i install it if the bats are good...ive heard that the green led strip will light up untill your start your car...does the tach or econmy move at all any other things? thanks

[rich4rdee]

on mine, exactly what you described happens. start the car up, revs up to ~1k, econ gauge points to 0 until i put it in gear.

[e30construction]

so does that mean your green led strip lights up when the keys are in position one(car not cranked just on)?

[rich4rdee]

so does that mean your green led strip lights up when the keys are in position one(car not cranked just on)?

yes

[e30construction]

ok well i installed the new cluster and everything works besides what i bought it for..thew tach and econmy still do not work...the led strip comes on and everything but no tach or econmy gauges...do the batteries need to charge for a while before they will work? and is there any wires right under the dash that are specific to the tach and gauge that i can look and see if theyr unplugged or cut?

[jlevie]

What car do you have?

[e30construction]

89 325i..not original motor but guy told me they did everything right...so i thought the bats were dead but that didnt fix it..po told me that when they installed the radio and speakers thats when it stopped working

[jlevie]

On that car the tachometer and econonometer data is provided to the cluster via C101 and those wires aren't near the radio. I suppose that a really ham-fisted radio installation could have disturbed those those circuits. With the cluster disconnected, you can run continuity checks from the DME to the cluster connector.

[e30construction]

ok well ive read the c101 thing earlier but have no idea where that is or what it is lol..im a noob when it comes to the electrics..theres a white box thing under my dash that has several places that things could plug into that arent being used could there be a plug that goes into that into that? and there were 2 nuts on the back of the cluster that were rly lose and i think i read that those are grounds or something..ive tightened them now but havnt tested the tach cus i figured that probly isnt it..


this is the white thing

no idea what these are

some of the hanging plugs

[Gregs///M]

MPG and tach signal come directly from the DME. Run through the cluster harness and into the SI board, then into the gauge. If the SI board batteries are dead, those gauges will not work.

If this guy sold you a cluster with the original SI batteries, I would assume they are dead. I would not continue troubleshooting until those batteries are verified dead or not.

Any SI batteries, not replaced recently, should be considered dead. I see guys, all the time, selling SI board that "works perfect" but have the original 22 year old batteries installed. Those are considered dead to me.

So start there, new batteries. If it still does not work, verify signal from the DME using a multi meter set to AC volts. Should see 1.5-6 volts with the engine running.

If you see the signal enter the cluster and still no gauge, the problem is related to the cluster. GL

[e30construction]

where can i go to have the batteries replaced cus thats something i cant do for the sake of messing something else up?

[Gregs///M]

Check out the thread in my signature about SI board repair.