Author Topic: Electrical problem, please help w116 300sd  (Read 163 times)

Benzboy

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Electrical problem, please help w116 300sd
« on: 11 March 2019, 01:28 PM »
Hey guys I have a 1979 300 SD, I started having electrical problems awhile back with starting the car. Intermittently I would turn the key and get a no click no start, all the lights would come on and everything and would not dim. But after I'd go wiggle the battery cable a few different times, it seemed like it would stop the issue. A few times I would just try turning the key again a few times and it would work. Now the car doesn't start at all . Did some research and ended up replacing the ignition switch. This did not fix the issue. So I'm considering replacing the starter, but I took the words off and halfway thru testing if they have power to the starter, I noticed that none of my lights were coming on in the car anymore, basically the instrument cluster lights. So I'm kinda at a loss on where to go or do from here. I'm gonna finish testing the power to the starter and go from there. Any advice? She's my daily and I miss her a ton
« Last Edit: 11 March 2019, 10:53 PM by Benzboy »

daantjie

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Re: Electrical problem, please help w117 300sd
« Reply #1 on: 11 March 2019, 02:04 PM »
Start simple.  Check all your ground straps for proper grounding.  There should be a heavy ground strap running from the negative terminal to chassis ground if I recall.  Also how good is your battery?  Have you checked CCA (Cold Cranking Amps)?
There should also be a terminal block under the battery tray.  Clean all these connections very well one by one with some electrical contact cleaner and copper brush, then reconnect them all nice and tight.
Good luck!
Daniel
1977 450 SEL 6.9 - Astralsilber

Benzboy

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Re: Electrical problem, please help w117 300sd
« Reply #2 on: 11 March 2019, 02:08 PM »
Brand New battery, full charge. Now I'm not getting power to anything at all. Will check the ground tray. The battery has been rewired at some point but appears in good condition. The transmission ground cable and battery ground cable appear to be in good health. How would I detach the transmission cable and clean it?

Benzboy

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Re: Electrical problem, please help w116 300sd
« Reply #3 on: 11 March 2019, 10:54 PM »
Had the alternator tested and it's fine. Really struggling to get the starter off. I also gotta figure out why all of a sudden I have no electrical

Benzboy

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Re: Electrical problem, please help w116 300sd
« Reply #4 on: 12 March 2019, 05:34 PM »
Update
Starter, alternator, and battery tested good. Gonna redo starter trigger wire and the starter wire that goes from starter positive to the harness tray underneath the battery and see if that helps. I'm sure the car wasn't getting power anywhere was because I had the positive cablesbdisconnected from the starter. The only wires leading from the positive post to anything else