So now my '72 164e is getting no signal to the fuel pump... The pump itself is OK, the fuse is good, the relays clicks when powered directly, so what's left? The "computer"? Should I make that assumption or can someone enlighten me as to another possibility?

Problem found! The ground wire that attaches to the right rear tail light was off, and that same wire apparently provides the ground for the pump! Go figure...

Grounding? If your meter has a continuity function, determine whether the pump is grounded properly by connecting from the ground wire on the car to the chassis. If not, try to jumper the ground side of the pump to determine if the ground wire is at fault. Also, clean up the ground location to rule that out.

Check the output of the fuel pump relay to make sure the wire going to the fuel pump is getting power.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

I think so... If it is the red one coming out of the relay, it is got 12v with the key On... But then there is no power getting to the fuel pump (at the pump). Is that the wire that powers the pump?

The yellow wire goes to the fuel pump.
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Eric

Hi Performance Automotive Service (formerly OVO or Old Volvos Only)

Torrance, CA 90502

You are right, but on this car the red is spliced onto the yellow, so yeah, we are talking about the same thing-- it has constant 12v with the key on.