Arthur,

Kind of a unique problem here. I say this because I've researched this code quite a bit...and in no case have I seen the issue be the relay. Nonetheless...

It is either the relay malfunctioning, or, the relay not receiving a signal to close the contact and send 12 volts to the pump.

I know this because I pried the cover off the relay and closed the contact by hand...and the pump comes on (by which I mean the electro-mechanical clutch engages and the pump runs).

Unfortunately, I've yet to be able to obtain a replacement relay. The local MB dealership parts department insists the part number I give them (126 820 20 26 = stamped on the relay itself) is a wiper relay - so they tell me they aren't able to help me. This part number isn't recognized (let alone stocked) by the vast majority of web-based MB parts specialists. I have found 1 company in Idaho that stocks it...so I guess I'll order a unit from them.

I thought you might appreciate hearing what I've learned, since despite researching this issue on 3 separate MB technical forums, I've never seen the relay to be the issue. Always either the pump is broken, or, it's a clog issue in the head ports or other valves and piping.

But I do have a question for you - maybe theoretical at this point. If the relay is not defective...this would mean the problem is the relay is not getting a signal from the ignition control module. Which would mean either the ignition control module is not signaling the relay to engage, or, the signal is not getting to the relay (due to a wiring issue).

Does my logic seem correct to you? Or can you think of another reason for the relay contact not to close that I am not aware of.

Well, anyway - thank you very much for your help is letting me know the relay in question was K17.

I'll let you know the results when I obtain a replacement relay and test my theory.

Jim

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Syntax26

1995 MB E420 (lowered)
1989 MB 300SE (sold to brother)
1975 MB 280 (sold)
One damn fine jacked-up golf cart