inoperable gas gauge

[bob66542]

first post in a while,been busy getting the car sorted w/ all new hoses,belts,fixing the charging problem(bad alt.rotor)rebuild rear wheel cyl,repairing exaust,and getting torn apart dash back together. have now put about 750km on it, and having a blast!please help trouble shoot my gas gauge! here are symptoms- gauge reads empty regardless of amt of gas in tank. disconnect elect. connecter on fuel sending unit in tank, gauge reads full. took known good tank sending unit from 108 parts car, connect elect. and lay in trunk on its side, gauge reads 1/4 tank- so i think, thats my problem- install known good used in tank- gauge reads empty.disconnect elect. connector, gauge reads full.(no change) where do i go from here?  also, my turn signals dont cancel. they should,shouldent they? car is a late 64 build date euro model.-bob

65 SL 230 4-sp. purchase 12-08-03

[ja17]

Hello Bob,
If you take your extra sender and plug it in (not installed), you should be able to turn it and watch the fuel guage work as the float moves in the cylindrical sender. The guage  should read full (max resistance) when unplugged. You can test the sender whith an ohm meter. The resistance should vary as the float moves in the cylindrical unit.
I would check the plug connections, take the back off the plug and make sure there are no broken wires. clean the connections and plug. The brown wire is ground. Make sure it is providing a ground. The entire rear wiring harness from the rear travels under the chrome door threshold on the driver's side.  Check to see if you have damaged or shorted wiring. Let us know what you find.

Joe Alexander
Blacklick, Ohio