Could be bad kickdown switch or kickdown solenoid. Also the bowden cable could need to be re-adjusted. Mine had the wire going to the solenoid broken at the connector. To test you would need to pull the plug at the solenoid and have someone engage the kickdown switch and test for 12V at the connector. A test light works here no need for a VOM. I have a spare solenoid if that is bad.... Give me a few bucks and I will dig it out of my pill in the garage and ship it to you. I replaced mine only to find the wire was broken. A couple minutes of my time and a soldering iron fixed that as the connector is serviceable.....

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....