I seem to be collecting these things, ... have 6 or 7 of them around here.

There was a question about the differences between gas and diesel CCUs on the 124s.

As all of the CCUs that I have are either from '87 diesels, or from various years of gas cars, I can make this comparison:

The '87 300D units that I have are missing one pin on the RH plug, and a couple more of the socket-end are missing. The 300E units have all pin-holes filled.

I've been running a CCU bought new last spring, for my '87 300D, it is the same part # as the BOSCH one in 300E cars. It might be a superceded part. The units from '87 300D are a different part number, and not BOSCH.

I re-installed an original '87 300D CCU yesterday, and noticed that the heater comes on faster than it did with the 300E units. The 300E units can take up to 1/2-1mile to start blowing when the car is started at below-freezing temps, the 300D blows sooner.

I don't know if the early 300D CCU can be used in the 300E, but the 300E units seem to work fine in the 300D. Might be the current 300D replacement unit, I don't have a way to check (although M-B sold me a 300E unit for my 300D). I also don't know if the 90s 300D uses the same part as the 300E.

Hope this helps someone get their 300D CCU working properly.

__________________

Gone to the dark side

- Jeff