Cliff Johnson

1994 e320 cab.... Replaced a dead battery, car started fine. But, a relay behind the fuse box started clicking constantly... even when the car was turned off. I tracked the sound to the 6-pin "multi-function relay". Found the model # and ordered a $50 replacement. Replaced the relay and that seemed to have solved the issue.
But, the next time I started the car, the clicking started again. The only way to get it to stop is to disconnect the battery. All functions in the car seem to work fine.... lights, turn signals, wipers, AC/heat. Any ideas would be highly appreciated.

Thanks in advance!
Cliff

SpiderAce

Cliff, I see no one has chimed in..... ouch.... Sounds like for some reason a circuit that energizes the relay, like the ignition switch, could be bad. Almost sounds like a short up-stream. Have you put a meter on it to see if there is power going to it with the switch off? Normally, I'd say it was an old relay, but it's not. So thinking a failed circuit, short, ignition switch, blower etc... it's just one of those things where you need a wiring diagram to determine what's connected. Give it time and someone on this forum will give you an answer. Lots of resources and ifnfo. Or, just win the Power Ball Lottery and then you can drop the car off at a shop for repairs and have no worries.... best of luck and don't give up.

Cliff Johnson

Thanks, Spider! I appreciate all the info!
The clicking now seems to come and go. Sometimes, I can start and run the car, turn it off.... and no clicking. Other times, it starts clicking as soon as it is
turned off.... continues for a few moments... and then quits. Hard to trouble-shoot! :-(

khomer2

You need a 2nd set of ears to determine where the click is coming from.
Finding a noise like a squeak, grinding, click, etc is one of the most difficult troubleshoots to resolve.
Also, you may need a mechanic's stethoscope or equivalent.

Cliff Johnson

The clicking definitely is coming from the relay.... you can feel it. But, replacing the relay does not solve the issue... :-(

khomer2

If you've replaced it (the relay), then it seems that something is shorting.
I know of others commenting in past about clicking relays in the same area as you describe behind the glove box/dashboard and others referring to clicking coming from the PS false floor board where the ATA is located.
Have you checked under the floor board?
There is a large relay that is a part of the ATA system.

Cliff Johnson

Yes...the clicking relay is behind the fuse box. Yes, probably an intermittent short. But, how does one know where to look?

khomer2

Photo of the 6 pin relay and its location?

Cliff Johnson

Thanks. I found the relay and replaced it. It is the one that is the farthest away from the fuse box, toward the rear of the engine compartment. It is called the "multi-function relay". But, the new one occasionally clicks, too.

khomer2

Occasionally clicks.
Then it seems that you havent resolved the problem.
Your referring to the relay tray behind the fuses (the one where you have to unscrew the cover)