Slanty

Hi All,

New member here! I recently purchased a 1979 911 SC converted to a Slant Nose/Turbo look.

I need help troubleshooting an issue where sometimes my Tach/Speedometer, Sunroof and pop-up headlights will work other times neither one will work.

They either all work or don't ...sometimes in the same trip. Any ideas of where to start troubleshooting this issue? Is there a master wiring harness I should be checking?

Thanks so much, looking forward to meeting the members here.

-Steve

masterdave

Grounds, Grounds, Grounds, a very common problem on these cars is corroded grounds. As this is a modified car some grounds may have been moved but if you have a haynes or bently manual it will list where all the grounding points will be. Basically you are looking for a point in which one or more brown wires is on a bolt that just screws in to an arbitrary point on the chassis. What has most likely happened is they have corroded and are intermittently conducting electricity. The fix is simple, just unscrew the bolt, sand the copper tabs on the wires to clean copper or tin depending on what they are, get the bolt on a wire wheel and clean it up or just get a fresh one. Then get a wire wheel or sand paper and clean up the area the bolt is affixed to. You may also find loose or not correct grounds while in there. The other thing to do is take all the fuses out and sand the tabs on the fuse panel to clean copper, I have fixed a few apparently serious issues there that turned out to be nothing more than corrosion.

The most important thing is to not start hacking in to the harness just yet. Many people start cutting up the harness to find the problem, I consider this a big mistake as usually the problem is simple. In my experience a wire in a sealed harness has almost never just stopped working. It is almost always the component or connectors. It takes a lot of current to melt wire. If you start cutting wires you end up with a harness made of crimp connectors and no one wants that.

That being said you may want to unplug all the connectors to the units and clean them with electrical contact cleaner. Then get some of that conductive grease stuff on them.

Regards
Dave

Slanty

Dave, thanks I will try to address the cleaning of the grounds as you described.


Regards,
Steve

1986 Targa

Check your fuse panel for a corroded or bad fuse contact.

Your sunroof fuse might look like this:

1986 Targa

Here's another pic:

Slanty

1986 Targa, I will check those fuses out as suggested - thanks for the helpful hints.

Regards,
Steve

1986 Targa

Also, try rotating the pertinent fuses.

Sometimes a poor contact can cause your issues.

Good luck,

Gerry