A/C control problems

[alan ream]

I just replaced the outside temp sensor on my 95 because it always read 50 degrees. Didn't help (damn). Any ideas. The rest of the system works OK. Not sure it's important, but when I start it up, the selector light blinks for about 1 minute, then goes solid. Any help is appreciated.

 

[alan ream]

Re: If same as '90- Electronic Auto A/C

Flashing display is a SYS fault detected & a SYS fault code will be stored. To read:

Push & hold the FAN up and the FAN down arrows at the same time for 5+ sec.
LCD should show "-00."
Push AUTO and LCD shows stored fault codes.

01/02 Temp Door Motor Circuit Fault
03 Ambient Sensor Open
04 Ambient Sensor Short
05 In Car Temp Sensor Open
06 In Car Temp Sensor Short
07 Solar Load Sensor Open
08 Solar Load Sensor Short
09 Low Freon
10 UART Failure

While in DIA Mode, press FAN up/down button to select parameter to be checked. Once selected, press FAN auto button for DIA value (LCD display). SYS parameters & normal operating ranges are:

0 SYS Faults 00-10
1 TEMP Setting in Degrees 60-90F
2 In-Car Temp Sensor 10(HOT)- 230(COLD)
3 Outside AMB TEMP Sensor 10(HOT)- 230(COLD)
4 Sun Load Sensor 50 (SUNNY) - 230 (DARK)
5 IGN SYS Voltage 0=9v. - 255=16v.
6 ENG Speed (RPM/25)
7 VEH Speed
9 SYS Mode 0-10 (Off, RECIRC, A/C, BI-Level, HEAT, DEFOG, DEFROST, VENT, DELAY, PURGE, MAN RECIRC.)
10 Blower MTR (Pulse Width MOD) 0= 0v. - 128 = 14v.
12 MIX Number 0= (COLD) - 255 (HOT)
30 Stored Full HOT Value (COLD) - 255 (HOT)
31 TEMP Door Travel Range 100-200
34 TEMP Door Feedback
35 Compressor on Time 1sec. increments
36 Number of Times below Critical Time
37 Software Version Number

A Minus (-) to the left of the parameter display range figure indicates an additional 100 to the display. (-130=230).

Get back with the stored fault codes and I'll add the flow chart diagnosis.

C'ya
D

I got a 03 trouble code. How can that be, I just replaced it on Sat and plugged it in.

 

[Rabbit]

After you change the outside temp sensor the outside temp will read 50* & show trouble code 03 until the car has been driven over 25 mph for more than 3 minutes or so. The outside air temp display will not increase until the you have driven 25 mph for more that 3 minutes.

 

[alan ream]

Re: If it doesn't clear as indicated in above post..

I would start by disconnecting power to clear codes (not certain if they will, but if they do), then recheck to see if code resets.

DIAG:

With measurements taken at 60 degrees f. outside ambient air, (approx. unless specified). Note: at 59 degrees, counts are 112 with 4450 ohms. At 68 degrees, counts are 97 & ohms 3514.

Does control head display 125 counts in pointer -19 with fault code 03 in pointer -00?

NO: Code 03 is intermittent. If no other codes were stored: use tool J 34089-A to check for opens & grounds in harness by moving harness. If no opens can be found (248 counts), monitor sensor at maximum cold & hot interior temp while driving vehicle. Replace sensor if out of parameter. If in parameter, replace programmer.

YES: Measure sensor resistance.
< 4kohms or >5kohms: Replace sensor
> 4kohms but <5kohms: Check for continuity in GND CIR 154 (BLK wire from B term of Outside Air Temp Sensor runs to S223 at I/P harness, behind CCM, then Heater & A/C Programmer GND, behind LH side of I/P, right of steering column).

NO Continuity: Repair GND
Continuity: Using adapter from J 35616, check for 5v reference at sensor connector CKT 735 (LT GRN/BLK from Outside Air Temp Sensor to Heater & A/C Programmer).

If REF VOLT is peresent: Code 03 is intermittent. If no other codes were stored: use tool J 34089-A to check for opens & grounds in harness by moving harness. If no opens can be found (248 counts), monitor sensor at maximum cold & hot interior temp while driving vehicle. Replace sensor if out of parameter. If in parameter, replace programmer.

If REF VOLT not present: Repair Open or Short to GND in CKT 735. If no Open or Short to GND, replace programmer.

What this boils down to is either: (1) an open circuit (bad connection); (2) bad ground; (3) bad sensor; or (4) bad programmer.

I'd concentrate on 1 & 2 (Ambient Sensor Open).

Best of luck.

C'ya
D

Thanks for the trouble shooting guide. However, you're a lot more savy on this stuff than I am. Can you resend, using "english". In other words, I don't follow things like "does control head display 125 counts in pointer -19 with fault code 03 in pointer -00" I'm sure it makes sense to you, but you're dealing with a relative newcomer here. Thanks, Alan