Dear Greg,

Good p.m. and may this find you well. Not owning a 1992 or 1991 car, I don't have the wiring diagrams for those model years.

However, on the 1993 940s, there is an overload protection relay, for the ABS control unit. This relay is mounted underneath the dashboard, on the driver's side (USA/Canada models).

Sometimes the ABS warning light comes on, and stays lit, because of transient power surges. Before going to the trouble of accessing the relay, power-down the entire electrical system, by disconnecting the negative battery cable clamp, from the battery. Put the clamp into a plastic bag, to isolate it.

You'll need your car's radio security code, to re-activate the radio. If you don't have the code, give the Vehicle Identification Number to a dealer's service dept., & they'll give you the Code.

Wait 15 minutes. Re-connect the negative battery cable clamp to the terminal. Start the car. Start the car. If the ABS light goes out, and stays out, you've solved the problem. If the ABS light comes back on, and stays on, you need to go further.

Turn-off the engine. Check the On-Board Diagnostic Codes (in the engine bay, against the driver's side strut tower [USA/Canada models]). The ABS system status can be reviewed, by putting the probe into Socket A-3. See the 700/900 FAQs, under site features, for how to get and interpret the codes. Read and post back with any codes, not explained in the FAQs. The ignition key should be in the start position - dash warning lights lit - but the engine should not be running.

If you want to inspect the relay's fuse, turn-off the engine. Again remove the negative battery cable clamp from the battery, and isolate it, in a plastic bag.

To access the relay, remove the panel under the steering wheel. There are two or three large, round, fasteners, that when turned, should drop out or be finger-removable. Pull the panel down and back. You will need to lay on your back, to look under the dashboard.

The relay is mounted against the side panel, to which the door is hinged (i.e., the side of the enclosure opposite the front center console). The relay is affixed with a metal clip. Push the relay upwards, to disengage it. There is no need to remove the wiring harness from the relay.

The relay is about 1" (25mm) square and about 2" (50mm) tall. I believe this relay's body is aluminium-coloured: it has a red plastic "cap". The fuse - it is Red ⎖ Amps] - is inserted into this red plastic cap. This fuse is a spade-type, the same as you find in the main fuse block.


Hope this helps.

Yours faithfully,

spook