Ollie88

Hey Team

The only info I can find on this is relay slot A and Fuse #4 (15amp). Since I have a 7.5amp fuse in position #4 I'm wondering whether the locations are different from year to year.

bbirdwell

The heat exchanger pump relay and fuse are the same for all years E55. Fuse rating is 15 amps. The harness change dates are 3/21/03 and 6/1/05, so there were three different harnesses, early, mid, and late.
For reference for others, the following link has the photo of the non-AMG fuel pump relay and fuse but which are used for the heat exhanger pump in the E55. In E55's, the fuel pump relay is hidden on the opposite side of the trunk.

http://cdn4.pelicanparts.com/techart...mall/pic15.jpg

From position 1 to 4, your fuses should be 30 amps, 30 amps, 7.5 amps, 15 amps.

austingtir

Is that fuse bridge pelican have shown there to make the intercooler pump come on full time with no relay? Or something else?

Ollie88

Thanks, the fact that someone had a lower amp fuse made me unsure. I used the fused bridge to check the pump and is all good. I did test the relay and that is fine too. Makes we wonder at what point the ECU triggers the pump to come on (I hadn't been able to make the pump come on by warming car up).

Ollie88

I used it to test the intercooler pump circuit without relying on the relay (in case it was faulty) or for the relay to be triggered.