BobbyT

Inside the front bumper on the driver's side, there is a sensor, but no wires connected to it. The parts list shows it as "outer sensor", part number 928 641 142 00. Is this an outside air temperature sensor for the OBC, which my car doesn't have?

p_carfan

I belive there could possibly be two the one that's not there is as you said is for the OBC.....The other part which you should have is for the A/C same part & part number different function.

I think..... , I'm sure I'll be corrected if I'm wrong

BS911

All 993s should have a wire harness with 2 plugs for temp sensors. Only those with the OBC should have the second sensor actually plugged in. Now as to why there is a sensor with nothing plugged into it... that's a good question. If you take your inner wheel well liner off then you could get a good look behind there and make sure that if it is the only sensor that it gets plugged in. It could certainly affect your climate control if it isn't plugged in. Do you per chance get hot air directly off the blue dot setting? Or no heat? Or some other air oddity?

BobbyT

Thanks, Brian. I will pull the fender liner and see what's up. The HVAC works just fine, but maybe not perfectly...

BobbyT

On the wiring diagram I found only one "outside temperature sensor", located in sheet 6, grid A60. It appears to be connected only to the OBC. Also, on sheet 3, looking at the CCU, I don't see a temperature sensor input. Finally, sheet 15, construction components, lists only one "outside temp sensor", located in the front LH bumper. All of this information is consistent with having only one sensor, and it not being used unless the car has OBC.

Please shine a flashlight in the bumper, take a look at this sensor on your non-OBC car and tell me what you see...

BobbyT

Okay, so I went out to the garage (very hot this time of day) and poked around a bit. It is easy to snap off the black plastic mesh grille in the air intake, and shift it to one side, which allows room to access the sensor. I found the wire that had been plugged into it, nicely taped off by the body shop that repaired a scrape on the LF fender. Now that it is plugged back in, I may notice some different behavior in the HVAC...

BTW, moving the grille to one side allows pretty good access to vacuum out the leaves and dirt from the AC condenser and oil cooler.

BS911

Just looked through the front of the bumper... sorry but I can't see the darned thing from there. Now it is possible that mine is not in the proper position though. I remember it didn't "snap" into its slot very securely so it may have relocated itself.

On my diagrams for the A/C components (I don't see sheet numbers as I have them from Alldata) I show an "Outside Temp Sensor Heating" at grid J21 connected to the CCU on pin G9 which is labelled Outside Temp Sensor. Not sure why the sensor is labelled with "Heating" in the name though. That is kind of weird. Maybe the CCU only uses that for proper heating operation and disregards for a/c operation.

Mine does have two plugs though... one for the OBC and one for the CCU. I guess one sure fire way to make sure the CCU is reading that thing is to take a resistance reading across G9 and G18 on the CCU connector and make sure you see something plausible there.

Don't know if this is helpful at all... I hope so, but sorry if it is just more noise for you to have to sort through now.