I have been trying to track down a rattle
in the dash area of my 1989 260E. Now, I'm
poking around the engine side of the dash
in front of the fire wall. Still have not fixed
the rattle, but discovered that a relay was very
warm. It is not being heated by anything around
it. It is getting warm by itself. I don't know
if this could have anything to do with the
rattle or not.

My question is:
"Does anybody know what the relay in the photo
does?" It's the one with the arrow pointing to
it. Is it supposed to be heating up?

And could this relay cause a rattle sound if
it was bad?




Here are some more images of the relay in question:



It does not make any noise when I shake it so
nothing is rattling around inside.



OBTW, the rattle sounds like a Geiger counter.
But, some days it does not make the noise at all.
It is not dependant on any of the usual things
(speed/heat/turning/braking, etc., etc.)





As I mentioned, this relay may not have anything
to do with the rattle but I don't think it is
supposed to get hot, is it?

Thanks guys,
- Jeff

__________________
- Jeff

1957 W121 190 (history)
1966 W108 250S
1967 W108 250S (parts)
1982 W123 240D (history)
1989 W124 260E

This appears to be the auxillary fan relay. I am not sure without the letter or # under it. But at any rate, the relay could be getting hot because it is carrying a high load. That is what they are supposed to do. I would measure the current through the relay and compare it to the realy's load (30a). IF it is acceptable, You are OK>

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

Thanks for the reply. The letter printed on the
black cluster (see photo of relay in car) is "F".

__________________
- Jeff

1957 W121 190 (history)
1966 W108 250S
1967 W108 250S (parts)
1982 W123 240D (history)
1989 W124 260E

In my experience these "ice cube" relays get quite warm to the touch. This is probably the low speed relay for the auxiliary fan. If it's warm out and you are running the air conditioning, I would expect this relay to be switched on almost continuously.

It shouldn't be hot enough to burn your fingers. My off-the-cuff guess is 120F?? Unless it's warmer than that, don't worry about it.