Bizzare? Kickdown Problem 107
 

I always had suspected that my kickdown didn't work on my 86 560SL. I checked the B switch functionality and it turned out that my shift knob shaft was positioned in such a way that it never engaged (it didn't go to B entirely, and would spring back. Not being in any other SL except my own, I thought that this was normal). I fixed this and as soon as I go to "B", my #7 fuse blows. Tracing the resistance to ground on the black wire, it is darned near 0 ohms relative to car ground. Not 20, or 50, or even 10, as you would expect a solenoid coil to be. Sure enough, the black wire on the under-accelerator kickdown switch is also at 0 ohms. I am certain that I did not cause this problem doing what I did; the resistance is the same with the connectors to all the switches disengaged - the black wire is at 0 ohms relative to car ground. If I had a spare solenoid, I could read the coil resistance and figure out what it should be. I have the shop CD and I know how to read schematics.

Suspicions:

1. It is likely that the fuel pump relay's source to the under-accelarator kickdown switch is current limited internally; that is, it I floored it in the past (I don't do this often), it simply current limited without blowing a fuse.

2. The previous owner or his mechanic moved the shift knob shaft over, thinking that no one uses this anyway.


Problem Sources:

1. A short in the wiring (this car is unmolested, so I'd be surprised about this), and no wires seem to be frayed (especially looked under the carpet).


2. The kickdown solenoid itself. This strikes me as an odd failure mode for a solenoid/relay (being much more likely to be open), but I'm willing to consider it.


If it is the kickdown solenoid, how big of a PITA is this to replace without getting seriously under the car. I hate going under the car!