91' XJ40 Soverign No Hazard Lights
 

Hazards won't flash when rocker switch is engaged. Searched the manual but cannot find a fuse linked to it. Advise?

Jagbro

Do your regular turn signals work when the ignition is turned on? Did you check for power to the back of the switch? Sounds as if your switch may be faulty. Did this just occur or did you purchase the car this way?

Hi Jagbro,

According to the 1991 Electrical Guide, the hazard switch receives battery power from fuse A1 (2 Amps) in the right hand fusebox (at the base of the right A-pillar).

The actual "flashing" function is handled by the Central Microprocessor (CPU). When the hazard switch closes, it connects pin 6 of the CPU connector LB13 to logic ground 4.

A known issue is water contamination of the CPU electrical connectors or the case and circuit board due to plugged A/C drains that allow water to pool under the evaporator and to slosh over onto the CPU when turning left.

You can download the Electrical Guide at the link below, courtesy of our member Gus and his website, jagrepair.com:

1991 XJ Electrical Guide

Please keep us informed.

Cheers,

Don

One place that can be the problem too is the "light logic module" in there one should check if there is any cold solders, known problem area too (was in mine -91 Sovereign)