NSA

My fuel pump won't run when ignition is hot and I'm currently at the DME relay. If I jump the 30 (12v in) and 87b (12v out to fuel pump), the pump will run when the ignition is hot, but when I try two different DME relays, the pump just won't run. Car is a 924S / 968 hybrid. 968 engine and DME, 924S basic wiring.

The DME has power going to 86 (hot) and 30 (always).

Pin 85 [1] - Ground to the DME/injector relay coil - OK
Pin 30 [2] - +12V directly from the battery - OK
Pin 86 [3] - Switched +12V from ignition switch (bus 15) - OK
Pin 87b [4] - +12V to the fuel pump, switched by the fuel pump relay - OK when jumped
Pin 87 [8] - +12V to the DME and fuel injectors, switched by the DME/injector relay - OK
Pin 85b [9] - 0V switched to the coil of the fuel pump relay from the DME, pin 20

How do I check 85b? It has 0v, but I guess this isn't the same as checking the ground.

Any ideas? Please don't say my DME might be fried.

snakoil

I can't remember how to test it but I did have my DME relay failed
You do know you can simply order a new one at your local VW dealer for 30$
Note that I ended up ordering 2 as the first DME relay I bought at the dealer was DOA
took me almost a full winter of fiddling to realize new item was DOA ;-)

If I remember well I ended up with a revised version of the relay that was in the VW golf.

NSA

I replaced the fuel pump, DME relay, and cleaned up the wiring and the car fired up as normal.

toms59

Very common problem with the DME relay as it gets hot and can fail with age.