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1999 SLK 230 Fuel Gauge Wonks

977 views 0 replies 1 participant last post by  cilynx 
#1 ·
I've done a bit of googling around and haven't found anyone with my set of symptoms, so I figure it's time to ask the experts.

I have a 1999 SLK230 and the fuel gauge works fine at the top and bottom of the tank, but jumps around or pegs up way off range when part-way through a tank of gas. I pulled the sender out, cleaned it up, and confirmed with a DMM that it smoothly reads from 0-200 ohms as you sweep the float through its range. When the sender is unplugged, the gauge reads empty. If I short the pins together going to the gauge, it reads full. I tested putting a set of known resistors across the connector leading to the gauge and everything below 40 ohms registers a predictable value in the empty-1/4 tank range. Everything above 100 ohms registers a predictable value in the 1/2-full range. Anything between 40 and 100 ohms causes the gauge to freak out.

Any good ideas?

Thanks in advance!
 
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