annoying 944 electrical issues
11-06-2007, 03:35 AM
#1
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annoying 944 electrical issues
Ok, I know from owning my previous 944 that these cars are notorious for electrical problems, I've eliminated a few problems i found on my car, but I still can't figure out a couple of things. For one my right foglight keeps dimming out and eventually blowing, despite new bulbs. I installed a momo steering wheel and now my horn doesnt work... I tested the power wire for the horn with a voltm. and it read 0... It worked before and i know the horns work fine because the stock alarm system still works... I installed a cd deck, and the wiring is fine i checked many many times and can't find a single problem but when i turn the volume up past 20 it shuts off then turns back on, when it was installed on my M3 it never had this problem. Anyone have any ideas? Fuses are fine, I know i need a new battery mines on its last leg, but would that cause these problems? I'm more of a mechanical thinker, me and wiring don't do so well together
11-06-2007, 04:47 PM
#4
Nerd Herder
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Check and clean all the grounds and battery terminals.. The extra draw may be causing excessive draw on the interior electrical system. Check this at night. See if the headlights dim when you tuen the volume up.
Bad battery would be indeed one of "the usual suspects"
Bad battery would be indeed one of "the usual suspects"
11-06-2007, 05:05 PM
#5
Burning Brakes
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Assuming your car wiring is relatively unmolested (i.e. some PO didn't really hack things up) the wiring diagrams are a good place to look to understand how things relate to one another electrically.
Starting with your fog lights - if the other one is OK, the place to start looking is the wiring to the right foglight itself. Power is fed from the main switched 12v through a fog light relay, then through fuse #15, leaves the fuseboard at terminal G6, where it splits into the left and right circuits, then directly to the foglights themselves. The only place where you could be affecting one light and not the other is after the wires split comming out of the fuseboard. Check the grounds as well. Another thing - these are halogen bulbs, so do not touch them with bare hands - use clean cotton or rubber gloves (without talcom powder)
For the horn, when you push the horn button on the steering wheel, you close the ground for the horn relay coil, which then routes power to the horns. The alarm horn is totally independent of the driving horn and the circuits are unrelated. Start by checking the slip ring in the steering column under the steering wheel. Jumper it to ground (ignition switch needs to be on) and see if the horn works. Underneth the car, there should be a small ground wire from the steering rack to the chassis. If that's missing or broken, it could be the source of your horn problems.
Lastly, for the stereo, it sounds as if your deck is shutting down to protect the amps. Are you still using the fader? if so, you should be running everything off the front or rear outputs of the stereo (just connect the front left and front right to the fader; don't use the rear outputs of the stereo at all) Most decks have 4 channel outputs now, so you could bypass the fader altogether (not too difficult in the early cars as all of the wires are right there) If you've already done that, then I'd suspect the speaker impedence is too low or they're somehow wired in parallel. Speaker grounds can be combined, but not the signal leads (+).
Good luck.
Starting with your fog lights - if the other one is OK, the place to start looking is the wiring to the right foglight itself. Power is fed from the main switched 12v through a fog light relay, then through fuse #15, leaves the fuseboard at terminal G6, where it splits into the left and right circuits, then directly to the foglights themselves. The only place where you could be affecting one light and not the other is after the wires split comming out of the fuseboard. Check the grounds as well. Another thing - these are halogen bulbs, so do not touch them with bare hands - use clean cotton or rubber gloves (without talcom powder)
For the horn, when you push the horn button on the steering wheel, you close the ground for the horn relay coil, which then routes power to the horns. The alarm horn is totally independent of the driving horn and the circuits are unrelated. Start by checking the slip ring in the steering column under the steering wheel. Jumper it to ground (ignition switch needs to be on) and see if the horn works. Underneth the car, there should be a small ground wire from the steering rack to the chassis. If that's missing or broken, it could be the source of your horn problems.
Lastly, for the stereo, it sounds as if your deck is shutting down to protect the amps. Are you still using the fader? if so, you should be running everything off the front or rear outputs of the stereo (just connect the front left and front right to the fader; don't use the rear outputs of the stereo at all) Most decks have 4 channel outputs now, so you could bypass the fader altogether (not too difficult in the early cars as all of the wires are right there) If you've already done that, then I'd suspect the speaker impedence is too low or they're somehow wired in parallel. Speaker grounds can be combined, but not the signal leads (+).
Good luck.
11-06-2007, 05:11 PM
#6
Burning Brakes
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I can add in a little on the horn issue...
The back of the adapter has a copper ring on it. That has to hit the metal tab on the tree. My adapter's ring was larger in diameter and therefore didn't hit the tab. Take your wheel off, and adapter, and measure the distance from the center of the column to the center of the tab, then from the adapter center to the ring. Bet you'll find the same thing. You have to adjust the tab so it hits the ring.
The back of the adapter has a copper ring on it. That has to hit the metal tab on the tree. My adapter's ring was larger in diameter and therefore didn't hit the tab. Take your wheel off, and adapter, and measure the distance from the center of the column to the center of the tab, then from the adapter center to the ring. Bet you'll find the same thing. You have to adjust the tab so it hits the ring.
11-06-2007, 07:09 PM
#7
"I know from owning my previous 944 that these cars are notorious for electrical problems"...
Ever own a British car? An MG or Jaguar makes the 944 electrical system seem bullet proof...
Ever own a British car? An MG or Jaguar makes the 944 electrical system seem bullet proof...
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11-06-2007, 07:37 PM
#8
Pro
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11-06-2007, 08:42 PM
#9
Nordschleife Master
kieth u need to stop wasting time on the computer when you could be spending time elsewhere, like finding my cell phone in your garage...
11-07-2007, 02:11 AM
#11
Nordschleife Master
I do need to find something to do, my car is just too perfect. Jk, I have two MBC sitting on my desk, I should install one soon.
Is the passenger side foglight grounded to the frame just behind the headlights?
Is the passenger side foglight grounded to the frame just behind the headlights?
