Hello all, I was under the dash of my 1992 740 and noticed this mystery relay and fuse very near to the ignition control module. The grey connector in the upper left appears to be a diagnostic connection BUT does anyone know what the relay and fuse item is for?
Thanks for helping.

 

If memory serves it's for the ABS... fuse blows, needs to be changed.

 

yeah, Volvo part 1363569 is a OVP (OverVoltage Protection) relay. Mercedes of similar era use one to protect the fuel injection electronics. Volvo used it to protect the ABS. If your system voltage spikes over around 15V, there's a zener diode in them that blows, then the fuse blows. on the Mercedes with Motronic (1993+ 6 cyl E class, for instance, with the 2.8 or 3.2L DOHC HFM-SFI system), they need replacing every 5-10 years as they will kill the engine. In the case of the volvo, it will just disable the ABS and give you a ABS fault light.

 

Thanks guys, I appreciate the shared knowledge.
Incidentally Pierce, I used your notes on stereo installation this past weekend. It saved me a lot of time, thanks for sharing that too.