Starter / Blower issue? (repost from general)

[1987E30]

I copied my post over from general technical - I didn't realize this section was for all electronics, not just car audio.

Hi, I am new to posting on this forum but have been "lurking" for a few months, and am new to the E30 world (but not to cars).

My 1987 325iS was very much an "almost junkyard" car, as a reference, but it did start and run when I purchased it.

Currently, turning the key to run or start does nothing, but it does power the overhead diagnostic display.

Jumping the starter with a wire from the battery terminal (on the solenoid) to the terminal from the ignition switch results in the blower motor coming on, but only when the selector is in high. Note that for this test, the key is not in the ignition at all.

Checking voltage, I have 12+ Volts at the battery terminal to the starter, but 0.2 Volts (very constant) at the ignition switch. There is 0 Volts when the key is in any position except start (which is expected), but I expected 8-12 Volts in start.

Jumping pins 11 and 14 in the diagnostic connector have the same effect as jumping the starter terminals - blower motor comes on, but only at highest speed selected. For both tests, the relays (K5 and K7) click when I make the connection, and click again when I release it.

Not sure if I have a bad K5 or K7 relay, or a bad Start Relay (it is an Automatic, so there is a start relay), bad starter, bad ignition switch (although i seem to be getting responses to run and start in voltage and light tests).

Also it may be worth noting, the sunroof and all power windows and power locks do not work either. No fuses are blown (but the 25 Amp window/sunroof circuit breaker may be blown). Either way, those problems existed before the start problems appeared, so I don't think they are related.

I don't think my blower resistors are to blame for the blower motor only working at high speed, because I do not even have the key in the ignition for that test, I am just jumping the two terminals on the starter with a push-button test lead. I must be applying voltage to S232 splice when I jump the wires, but I'm not sure how.

Kind of a lengthy first email, but any help is appreciated. Thanks!

[StereoInstaller1]

OK, welcome to BMW starters...you are testing the wrong wire.

Some brilliant German son of a bitch decided it was too dangerous to allow you to run your heater or roll the windows down when cranking the motor, so they use a wire off of the starter to open 2 relays that do just that.

That wire is green/black and runs the "unloader" relays. It is the upper terminal on an M20 starter. It should show ground at all times except when the starter is engaged, when it should show positive.

There is a second terminal just below that with a small black or black/yellow wire that is a normal +12V starter wire.

My guess is that someone put both wires on the unloader terminal.

Good luck!
Luke

[1987E30]

Thanks for the reply! I don't believe I am testing the wrong wire. I'm not sure which green / black wire you are referring to. There's a red wire and black wire from the battery and alternator on one terminal, and the bk/yl wire on the small terminal to the ignition switch. The unloaded relays come from s233. On 1988+ models, there's another wire on the starter (mine is 1987)

There is no "unloader terminal" on the starter. Just a battery, and ignition switch. The unloaded relays (which come on every car), take power away from everything unnecessary during startup.

Any other suggestions?

[StereoInstaller1]

Thanks for the reply! I don't believe I am testing the wrong wire. I'm not sure which green / black wire you are referring to. There's a red wire and black wire from the battery and alternator on one terminal, and the bk/yl wire on the small terminal to the ignition switch. The unloaded relays come from s233. On 1988+ models, there's another wire on the starter (mine is 1987)

There is no "unloader terminal" on the starter. Just a battery, and ignition switch. The unloaded relays (which come on every car), take power away from everything unnecessary during startup.

Any other suggestions?

Your data is incorrect.

The unloader relays run ONLY the windows and HVAC fan. The relays are most certainly connected as I described.

So, it sounds like you need to download the electrical troubleshooting manual: www.wedophones.com has it.

You will find details in the ETM.

Good luck!
Luke

[1987E30]

Already have an ETM. Don't believe I'm mistaken about the electronics, but are a blower motor and hvac fan not the same thing? I wa referring to the hvac fan, and calling it the blower motor (probably incorrectly)

[1987E30]

Fuse 10 provides power to one end of the relay, and the starter provides power to the relay from the other end. When the starter is running, coil is reenergized, so nothing goes from k7 to blower motor. Since my fuse 10 wasn't working, the power that would normally kill the relay instead activates it.

My information about the splices was in fact incorrect. But my problem ended up being that fuse 10 does not get consistent power, and the starter is gone either way.

Thanks

[StereoInstaller1]

Fuse 10 provides power to one end of the relay, and the starter provides power to the relay from the other end. When the starter is running, coil is reenergized, so nothing goes from k7 to blower motor. Since my fuse 10 wasn't working, the power that would normally kill the relay instead activates it.

My information about the splices was in fact incorrect. But my problem ended up being that fuse 10 does not get consistent power, and the starter is gone either way.

Thanks

Well, sounds like you are getting it sorted out...but if you want a quick fix, just ground that green/black and it should work...as long as fuse 10 is not flaky.

I so wish the fuseboxes were oldschool hardwired, I hate the circuit board crap, they are just not "fixable".

LMK if I can help.

Luke

[1987E30]

Thanks a lot for the replys / help! fuse 10 slot was such an annoying pain to track down, because it's not like the fuse was blown, but just didn't make good contact.

I'm not familiar at all with how fuseboxes are wired, but half of me wants to grab a new fuse box from the junkyard. Is that even possible (Given the amount of wiring that goes through it to the rest of the car?)