My #5 fuse keeps blowing when I engage A/C (NOT blower motor) and M.B. Doc suggested checking draw at the A/C clutch. Guess the next question is: Is this clutch serviceable or replaceable? Are there any "tricks" like the brushes in the alternator that might forstall the purchase of a new compressor (ouch) that is otherwise functioning properly?
Thanks for your help!

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Ralph S. Robbins
Boca Raton, FL
'86 420SEL
163k (as of 10/01)

Like Doc said look at the current draw. It should be about 3amps. Bad coils are a very common problem on Hondas with similar Nippondenso compressors. I do not know why MB's don't seem to have the general problem. They do have the problem occasionally and the draws I have measured are in the neighborhood of 10amps.

The coils or all of the clutch can be replaced separately. The coil is the last item off the front of the compressor. MB sells rebuilt clutches complete for a reasonable price. The problem is getting the right pieces. There were a couple different versions of the 10p Nippondenso compressor used. They are easily replaced in total by a current version but getting repair parts requires getting the right component for a right component. If the compressor is a aftermarket rebuilt there are all kinds of different individual pieces and the old pieces may not be acceptable as cores.

If you compressor is a virgin a rebuilt clutch exchanged as a whole is the way to go.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Check the current draw on the air pump clutch. You may find that it is causing fuse #5 to blow, if memory serves me correctly.

Check this if you decide on a DIY. Clutch/coil removal covered in the beginning. http://www.pelicanparts.com/techarticles/911_Nippondenso_rebuild/911_Nippondenso_rebuild.htm

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Ralph,

I have a core from an 87 300 SDL you can have for shipping (from NC). When it siezed the clutch was working. If you can tell me how to get just the clutch off it could save some shipping costs. Edit... It is a Nippondenso 10p15C compressor.

Chuck