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.
1991 BMW 735iFACTORY OEM SERVICE PROCEDURE
Control Units/Modules
CONTROL UNITS/MODULES LOCATION
| Component | Location |
|---|---|
| Anti-Theft Module | Under left side of rear seat, in front of rear fuse/relay box. |
| Automatic A/C Control Unit | Behind front footwell, ahead of plenum. |
| ABS Electronic Control Unit | In electrical box, behind right front shock tower. |
| Check Control Module | In front fuse/relay block. See Figure . |
| Chime Module | Behind left side of dash, on hush panel. |
| Cruise Control Module | In electrical box, behind right front shock tower. |
| Crash Control Unit | In front fuse/relay block. See Figure . |
| Electronic Heater Control Unit | Behind front footwells, ahead of plenum. |
| Electronic Throttle Control Unit | In electrical box, behind right front shock tower. |
| Final Stage Unit | On left side of right footwell. |
| General Module | In rear fuse/relay block. See Figure . |
| Headlight/Foglight Module | On left side of engine compartment, in auxiliary fuse/relay block. See Figure . |
| Infrared Locking Control Unit | In rear fuse/relay block. See Figure . |
| Light Control Module | In front fuse/relay block. See Figure . |
| Level Control Unit | Under car, to left of differential. |
| Memory Seat Control Unit | Under driver's seat. |
| Motronic Control Unit | In electrical box, behind right front shock tower. |
| Relay Module | In rear fuse/relay block. See Figure . |
| Servotronic Control Unit | By driver's foot rest, behind speaker. |
| SRS Diagnostic Module | Behind left side of dash, left of steering column. |
| Trailer Control Module | In left side rear corner of trunk. |
| Transmission Control Unit | Behind right kick panel. |
| Wheel Camber Control Unit | Under car, above right side halfshaft. |
Factory Service Tools
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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.