As our first day of travel from Maine to the PCA Parade in San Deigo came to an end amidst a down pour outside Syracuse NY, I switched on my running lights (914-6 Euro) only to find my tach dropping to 1000 rpm (engine continued to purr at 4k) and the high beam indicator lamp lit up without the headlights on. No noticeable change in any other gauges of functions. I can flash my driving lights without any problems.

I'm open to any and all suggestions. Though I don't PLAN on night time driving for next couple of days, I would like to remove the nagging question of what might be happening (a short somewhere?)

Further diagnosing, I find that if I remove my combo instrument light (lead), all is well. It appears that something in the tach instrument is find a ground? through that lead. Removing and taping up the lead is a work around but no fix.

Anyone out there?

The gauges in a 914 are isolated from ground. Each gauge has a ground connection to it (brown wire) made sure the wires are there. A good example
of this is the instruments gauge lights, they are luminated thru a black/blue
wire to each bulb therefor each gauge must have a return ground to light the
bulb.

certainly sounds like a (missing) ground issue. time to dust off your multimeter!
Andy

PS: while you're in there, check all your fuses and rotate them with your fingers to make sure they're seated correctly. they sometimes rattle lose ...

One more oddity. If I dim the instrument lights, the tach is fine. As you turn the light level up, the tach reading drops.

I'll pull the gauges and check for a poor or missing ground, and the fuses, after I have a couple of drinks to steady my hands. Just arrived in Dayton, OH after an 8 hour sprint.


I appreciate the feedback.

do you have a defroster light (square black box) on the center tunnel, just in front of the shifter?

if so, remove the top, unscrew the socket and check the back. i bet the cable for the light is grounding to the chassis ...
Andy

I sure hope you get the electrical problem fixed. My daughter drove her 914 to Sacramento for the 2000 Parade and it was an advinture, mainly the heat. I imagine you are planning on driving at night across the desert since it has gotten HOT out there, over 110 in Phoenix now. If you get to Phoenix I hope you go south to Gila Bend and then over on I-8 instead of I-10 as you'll miss the people driving to/from LA and they are sometimes a mess and the moutains are prettier too. There are some places where you can see Mexico actually and make sure to stop and be very curtious to the border patrol at their checkpoints!!!!

Nope. This my 914-6. I suspect it is a bad ground wire on the tach. I couldn't get to it tonight. I'll need to fine a 28 mm socket to remove the steering wheel for better access. Good reason to take a break from my travel westward tomorrow.

27mm, if i'm not mistaken ...
Andy

I knew that. I was just testing you. <grin>