Hi,

seeking advice / experience regarding the troublesome Combination Relay. My wife's 300SL had issues with wipers since a while, first intermittent function then finally wipers went dead altogether. Switch and motor checked fine. Discovered that when supplying 12V to the number 11 fuse (wiper, etc.) the wiper started to work as expected, but only for a while ... next day same problem, applying 12V to fuse 11 again, things started to work.

Figured problem is with the combination relay and found a good used one on eBay. Installed it and everything worked fine from the get-go, except ... after a couple of days wipers would completely stop working again plus seat adjustments, radio and 12V outlet didn't work either.
All fuses checked fine. Interestingly enough, everything started working again after bridging 12V to fuse no. 11!

Wondering if I have another bad combination relay or if there is any other related issue (relay, connector, etc.) that "disconnects" the combination relay somehow and where the "connection" get's re-established by applying 12V to the fuse?

Any tip, hint or explanation highly welcome :-)

Thanks much in advance.

 

it is unusual for one to go bad in the first place, let alone two. anything is possible. those fuses can get fine cracks that are hard to spot.

 

Thanks, brookings.

Learned that the CF (Convenience Features) Relay K24 might be involved with my problem. Anyone knows where this relay is located on the 1990 R129?

 

in the drivers side fuse and relay box, of the five square relays in a row, it's position A, the furthest back

 

I have replaced the seat switch and then discovered there was no power to the fuse receptacles for the seat adjustments. I replaced a surge relay behind the battery and I am considering replacing power seat relay behind the fuse box, no clue what I'm doing, hit and miss, any suggestions?