Hi I have a 1990 xjs convertible which is driving me crazy. When I put my foot on the brakes the fuse for the direction indicators blows. No corrosion anywhere no modifications . Hazard lights function fine when brake pedal depressed but not turn signals . All bulbs good. Replaced fuse many times to try to trace fault but to no avail. Any suggestions? Many thanks

 

You need a wiring diagram. You can find one on line. Look for commonalities between the turn signals and the brakes.

 

If it is fuse no.5 looking at the circuit diagram this is common to the indicators and stop lamps.

To find the cause, do the following, testing each time.....

Disconnect the connectors at the brake lights. Then work your way back towards the fuse, disconnecting connectors.

You have a short after the brake switch 18 in the diagram in the green area. It could be in the 301 the stop lamp failure sensor or in the wiring harness.

My first guess would be a chafed wire in the harness.

 

Thanks a lot guys-got wiring diagram from Internet and traced down brake light failure sensor under center console and found screw securing center console had worn thru insulation causing short- took a couple of hours but working great now. All the best . Peter