Expert: Roland Finston - 6/1/2011

Question
QUESTION: You may not be able to help me and that's ok but i thought i'd ask anyhow. I have a 2000 sunfire 2.2 and i believe i have wiring issues. When i start my car and put it in drive the dash beeps three times, a yellow light comes on and the service engine light comes on and the driverside headlight is dim and my blinkers stop working when the car gets warm, you can still do the blinkers manually but they dont blink normally on their own...I would like to know where exactly to look for these wires as i'm not familiar with wiring but am trying to learn. Thank you for any help!!

ANSWER: Hi Heather,
I of course don't have wiring diagrams for that General Motors vehicle. Can you tell me if the yellow light is labeled in any way? Does the manual say anything about what the dash beeping three times might mean?
One thing you can try is to get a readout for fault code numbers that the engine controller has stored in its memory. On some cars you turn the ignition switch: On-off-on-off-on and leave on doing that in 5 seconds or less elapased time. Then watch the odometer window to see if the mileage reading changes to show any 4 digit numbers. If not. then take the car to an Autozone parts store (or similar nationwide autoparts store) where they will get the readings by a plug-in code reader, for free. Ask for the numbers, what they mean, what they recommend doing, and about how much it will cost. Then write back and tell me the results and we'll compare notes. The slowing down of blinkers, dimming headlamp, etc suggests that the charging voltage or the operating voltage of the battery is being dragged down. This could be due to a short circuit or to a failing alternator or its wiring. Perhaps the code will tell us which.
Roland
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QUESTION: I did a code scan and came up with C1235-Abs speed sensor or speed sensor wiring. I don't know if this is the result of the problem or not. I do have one, i have the right rear one but i dont know where to look for it. Also, the yellowish light is a light on the left side of dash and it flashes and then goes out but the right side blinker light stays lit up. I once asked someone else and they told me it's the front lamp wiring harness but i dont know where that is either and tried to order one but i cant even find one that's called that...Thanks for any help..

Answer
Hi Heather,
Might the yellow light be related to the ABS system? I don't have a manual to verify the C1235 but if you will remove the rear wheel (if that is the one you think is the problem) and look closely at the inner edge you may find some sort of groves going all the way around it. Those are what the sensor observes to determine the rotation speed of the wheel. The sensor is mounted on the wheel suspension member that would place it very close to that groved ring on the inner side of the wheel. Try cleaning the sensor tip and the groves in the wheel and also check the sensor wiring.
On the front headlight I would begin by removing the electrical plug to the lamp and cleaing the contacts on the bulb and in the plug as the most likely reason for poor electrical contact causing low current flow to the bulb.
On the turn signal issue I would spray some electronic contact cleaner into the interior of the turn signal switch. That cleaner is sold in electronics parts stores in a spray can. If that doesn't help then listen for the sound of the flasher unit and locate it by its sound under the dash. I would suggest replacing that flasher unit to see if that would correct the turn signals. The same flasher operates the emergency flashers, so if those also fail when the car is warmed up that would implicate the flasher unit. If it doesn't fail then I would focus on the turn signal switch internal contact cleaning with the spray cleaner.
I am really out of my area of expertise with the car however. Is there an Expert for your GM vehicle here at AllExperts?
Roland