Hey guys, I put up a similar forum on a car forum site but it's been a few days and no one responded to it, not sure why not. Anyways, I think I should seek some help with some DIY electrical guys who know a little more about wiring than I do. So here's the deal, my car has some electrical wiring issues with the ambient (outside) air temperature. My cluster is reading -40˚F which after doing some research means that it's an open circuit. Before, there was a notable short in the wiring which caused the temp to read 122˚F.
I fixed the short which was a group of wires pinched between two metal pieces. I tested for voltage coming out of the connector and got no reading. Right before the pinch I shaved off a little bit of insulation and tried again (put one wire to the wire and one to ground on the car). So yes, I got a reading so I figured that pinched wire may have some issues with it (I also measured right after the pinch and again got no voltage so the pinch HAD to be my problem).
The way the wiring works (I'm almost positive) is that one wire goes into the temperature sensor with a set voltage in it (about 3.7V I believe) and the temperature sensor has a resistor thing built in it which is affected by the outer temperature. And then the new voltage goes into the other wire which sends the new electrical signal into the instrument cluster because that is the way it is connected- directly into the cluster.
The other wire had no voltage in it which I assumed was normal but I measured continuity (beeping feature on my multimeter) right before the pinch and right after the pinch and it beeped so I figured that this pinch wasn't as bad so I left it alone. Anyways, my reading is still at -40˚F which means that there must be an open circuit somewhere but didn't I just fix it? Take a look at this link which describes the code I'm getting
www .helpforcars. net/obd_codes/p0073_bmw. html
(^^^remove spaces after www, before net, and before html^^^)
The temperature sensor is new so I doubt that that's the problem. I'm pretty positive I fixed the open/short circuit so I don't think that's it either. Could it be a poor electrical connection? Any help or advice or methods of proper testing would be of great help. Thanks!
I fixed the short which was a group of wires pinched between two metal pieces. I tested for voltage coming out of the connector and got no reading. Right before the pinch I shaved off a little bit of insulation and tried again (put one wire to the wire and one to ground on the car). So yes, I got a reading so I figured that pinched wire may have some issues with it (I also measured right after the pinch and again got no voltage so the pinch HAD to be my problem).
The way the wiring works (I'm almost positive) is that one wire goes into the temperature sensor with a set voltage in it (about 3.7V I believe) and the temperature sensor has a resistor thing built in it which is affected by the outer temperature. And then the new voltage goes into the other wire which sends the new electrical signal into the instrument cluster because that is the way it is connected- directly into the cluster.
The other wire had no voltage in it which I assumed was normal but I measured continuity (beeping feature on my multimeter) right before the pinch and right after the pinch and it beeped so I figured that this pinch wasn't as bad so I left it alone. Anyways, my reading is still at -40˚F which means that there must be an open circuit somewhere but didn't I just fix it? Take a look at this link which describes the code I'm getting
www .helpforcars. net/obd_codes/p0073_bmw. html
(^^^remove spaces after www, before net, and before html^^^)
The temperature sensor is new so I doubt that that's the problem. I'm pretty positive I fixed the open/short circuit so I don't think that's it either. Could it be a poor electrical connection? Any help or advice or methods of proper testing would be of great help. Thanks!
