Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSSAAB1994900 SE, 4D HATCHBACK, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)HEATING, VENTILATION & A/C (HVAC)HVAC CONTROL SYSTEMSA/C-HEATER SYSTEM - AUTOMATICTROUBLE SHOOTINGNO COMMUNICATION BETWEEN A/C-HEATER CONTROL PANEL & ISAT
1994 Saab 900 SE, 4D Hatchback, Automatic
No Communication Between A/C-Heater Control Panel & ISAT
1994 Saab 900 SE, 4D Hatchback, AutomaticSECTION No Communication Between A/C-Heater Control Panel & ISAT
- Ensure communication can be established between instrument cluster and Saab Information Display (SID) panel. If communication cannot be established, go to step 3). If communication can be established, go to next step.
- Connect breakout box to A/C-heater control panel. Check voltage between pin No. 1 (Black ground wire) and pin No. 11 (Brown/Orange wire). Also check voltage between pin No. 1 and pin No. 13 (Blue/Orange wire). Voltage should be about 2.5 in both instances. If voltage is correct, go to next step. If voltage is incorrect, go to step 4).
- Check data link connector for loose or damaged pins. Check voltage between a known good ground and data link connector pin No. 1. See Fig 1 . Also check voltage between ground and data link connector pin No. 9. Voltage should be about 2.5 in both instances. If voltage is correct, go to next step. If voltage is incorrect, repair wiring harness as necessary.
- Check A/C-heater control panel (control module), its connector, and wiring harness for loose or damaged pins. Ensure the A/C-heater control panel's display goes out when BLACK PANEL push button is pressed on SID. If necessary, replace A/C-heater control panel. See BEFORE REPLACING A CONTROL MODULE under REMOVAL & INSTALLATION.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.