Relay clicking behind dash
 

On a long drive, I started to hear an electrical clicking. Almost exactly like a relay clicking on and off, or just like the wiper circuit clicking.

I pulled out all of the relays in the relay box mounted to the underside of the dash, the three circuit breakers in the interior fuse box and my aftermarket remote starter door lock relays and brain box. But the clicking continued. It seems somewhat random, but happens more often after I've driven for a couple hours.

Any ideas?

The VERY first thing to be sure of is that your motor oil is at the proper level. This might sound over-the-top, but running low on oil often comes into the cabin as the sound of a somewhat electrical type of clicking, that get progressively louder. Many people think its an internal problem, not realizing its coming from the engine compartment. By the time it gets loud enough to be obvious, they have sometimes done a lot of damage. So just rule that out first, easy check, free.

You haven't mentioned the year of your vehicle, but next time you get a chance, pop the hood while engine running and listen up around the firewall (in the engine compartment), there are a variety of things in that area that can click. I have one right now that sounds just like a relay, but appears to be part of the vacuum plumbing.

A mechanic's stethoscope is an amazing tool for finding noises, and diagnosing lots of things.

Everyone should keep one in his tool box.

Thanks BlueRidge, I have a stethoscope and use it regularly. Only thing is, it's hard to hold it under the dash when you are travelling at 60MPH down the freeway.

Jordan: Yes the oil is at the proper level, it's not engine related. It's for my 93 XJ.

Hmmm. You haven't got that contortionist thing down pat, I guess. :)


This might call for a partner....

I think I got it sorted tonight. Fairly certain it was coming from the brake pedal switch, I could get it to make the same noise by wiggling the pedal side to side. I cleaned the contact points between the switch and the pedal bracket, and applied a little dab of grease.

I'll know for sure after my next longer journey. Cheers