# Electronic problems **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** gauges, mercedes-benz, sl-class\ **Created:** [August 19, 2009, 7:16pm UTC](https://community.cartalk.com/t/electronic-problems/35290 "2009-08-19T19:16:54Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![eefox49](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/eefox49/32/1398_2.png) [@eefox49](https://community.cartalk.com/u/eefox49)\ **Post date:** [August 19, 2009, 7:16pm UTC](https://community.cartalk.com/t/electronic-problems/35290/1 "2009-08-19T19:16:54Z")
It’s an '86 mercedes 500SL (euro model). I recently had the battery removed for a check. I had starting troubles and thought it might be the battery. It checked out OK, but ever since it was replaced the power windows only work when a door is open! The instrument panel gauges don’t work, including speedometer and odometer, but the clock works fine. The turn signals don’t work and the brake lights don’t work. What would cause all these things to go out at the same time??? ---
**Author:** ![oldschool](https://avatars.discourse-cdn.com/v4/letter/o/e19adc/32.png) [@oldschool](https://community.cartalk.com/u/oldschool)\ **Post date:** [August 19, 2009, 9:36pm UTC](https://community.cartalk.com/t/electronic-problems/35290/2 "2009-08-19T21:36:54Z")
Accidently installing the battery backwards for a brief time. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [August 20, 2009, 2:21pm UTC](https://community.cartalk.com/t/electronic-problems/35290/3 "2009-08-20T14:21:05Z")
Sounds like a ground problem to me. Start from the battery negative terminal and inspect the ground wiring, any wire strap(s) from the car body to the engine, any ground wires that come out of harnesses and bolt to the body or engine. ---
**Author:** ![Cougar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cougar/32/21348_2.png) [@Cougar](https://community.cartalk.com/u/Cougar)\ **Post date:** [August 20, 2009, 2:57pm UTC](https://community.cartalk.com/t/electronic-problems/35290/4 "2009-08-20T14:57:33Z")
If you haven’t checked the fuses and fusible links yet to see if there is a problem there then I suggest you do that. If there isn’t a problem there then there may be problem with the grounding as Circuitsmith suggested. You could try adding a ground jumper wire from the battery and to a good ground point to the dash area and see if that helps. The window problem may be due to a broken wire in the door jamb. That is a very common problem with the power windows after some time. If that is correct you may be able to replace the small harness in the door. ---
**Author:** ![eefox49](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/eefox49/32/1398_2.png) [@eefox49](https://community.cartalk.com/u/eefox49)\ **Post date:** [August 21, 2009, 6:21pm UTC](https://community.cartalk.com/t/electronic-problems/35290/5 "2009-08-21T18:21:36Z")
Thanks for the help everyone. Turns out there was a short in the wiring at the trunk hinge. This kept blowing fuses. Once I fixed the short and replaced the fuses, all is well. ---
**Author:** ![Cougar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cougar/32/21348_2.png) [@Cougar](https://community.cartalk.com/u/Cougar)\ **Post date:** [August 22, 2009, 2:51am UTC](https://community.cartalk.com/t/electronic-problems/35290/6 "2009-08-22T02:51:28Z")
Glad to hear you got it fixed and thanks for the feedback. ---
**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\ **Post date:** [August 22, 2009, 7:04pm UTC](https://community.cartalk.com/t/electronic-problems/35290/7 "2009-08-22T19:04:49Z")
It’s nice that you found where the problem was; but, HOW did you find it? The trunk lid is a fair distance from the instrument panel. What’s the connection? ---
**Author:** ![eefox49](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/eefox49/32/1398_2.png) [@eefox49](https://community.cartalk.com/u/eefox49)\ **Post date:** [August 22, 2009, 10:44pm UTC](https://community.cartalk.com/t/electronic-problems/35290/8 "2009-08-22T22:44:10Z")
Just lucky. Brake lights and turn signals didn’t work. I was noodling around in the trunk and noticed the short…taped it up…new fuse…bingo!