Over the weekend, I set out to trace the short in the circuit associated with fuse #15 in my '89 420SEL, and I ran into problems using the instructions Scott supplied above. Here's the thing:

1) When I connected one lead of my ohmmeter to the side of the #15 fuse terminal away from the power supply and the other lead to the frame of the car (as instructed), I got not just a low resistance reading, but a NO resistance reading--just like touching the leads to each other. This wasn't what I was expecting.

2) To convince myself that the technique worked (as I understood it), I removed another few fuses from their respective sockets and tested them in the same way. To my surprise (and frustration), a lot of them (particularly the ones with low amperage fuses) gave the same NO resistance reading. Some (including #15) did so from BOTH fuse terminals--which I REALLY don't get, since the battery terminals were both disconnected. Am I dealing with undetected shorts in all these circuits??? I don't think so, but how to explain my test results otherwise?

I don't get it. What am I missing here. I expected #15 to behave differently than all the others, but it isn't.

HELP! (Please...)

__________________
Eric

1991 560SEL-Euro (214,000 miles)
1989 420SEL (Retired from daily use at 325,000 miles; Use as donor vehicle)