1993 xj40 base

I have a light out warning, thought it was just a bulb that was not the correct size for the cat. Bought new bulbs and replaced. Checked all the outside lights everything OK. Backed the car close to garage to check stoplights, they seemed fine. When I stepped on brake I heard a distinctive click ever time I pushed on brake? It was coming from passenger side below the glove box and the floor board? What could this be ??

 

The clicking comes from the drive shifter and from the rear right corner of the trunk. It only makes this sound when in PARK. It seems to be coming from the module that controls the brake lights backup lights and the FUEL pump relay. I have been having trouble with cold starts sometimes taking up to ten seconds for the cat to start. I did see a blue relay that I will replace it did seem warm to the touch.

 

Saw this on the way down to my usual forum destination in the XK8 section.

It's quite a few years since I had an XJ40 so I no longer have the circuit info available. Your mention of trouble with cold starting brought back some bad memories!

The clicking you describe is often due to a relay 'making and breaking' instead of closing properly. The one next to the drive shift is likely to be the interlock relay. For the one in the trunk, a second pair of ears and hands would help you track it down. Whilst you're starting the vehicle, have someone at the trunk try to hear which one it is or by putting a finger lightly on the relay case, feel for the 'pulsing' of a faulty one.

Relays are tricky to test as, unlike fuses. you can't see any fault with them. Easiest way to do a quick check on a suspect one is to swap with an identical one from elsewhere on the vehicle. They shouldn't even get warm, let alone hot.

Hope my 2 cents worth from very long ago XJ40 knowledge can get you a bit closer to the source of the problem.

Graham