MattSlay

I have removed the instrument panel from my 944 so that I can replace the light bulbs on the back of all the gauges and dials. I figure this will take me a few days to get it completed and back in the dash, so I'm curious if I could still drive the car during that time? I mean, will it run properly and everything with the instrument panel removed? I know I won't be able to see the speed, RPM, and other indicators, but I'm wondering if it would prohibit the car from actually cranking and driving properly?

931guru

Yes. Of course, you could always try it and see...

MAGK944

Yes, yes, no.

StoogeMoe

Sure you can drive it. And when the cop stops you for speeding, and asks you how fast you were going, you can say "I don't know!" without being a wise guy.

marc abrams

I know that I said that I was done with Rennlist a while back due to obnoxiousness here on this forum. But I also would hate for the OP to be stranded with a dead battery from bad advice giving on Rennlist.
The alternator may not charge due to a lack of the exciter circuit with the instrument cluster removed from the car. You can however manually excite the alternator with a test light from battery positive to alternator D+ terminals if you need to drive it.

MattSlay

@marc abrams - Thanks for taking the time to give this valuable info...

marc abrams

Your quite welcome Matt.

MAGK944

@marc abrams You may not be aware that the stock alternator on our cars has an internal voltage regulator that does a good job of self-exciting the alternator. It does fine without the exciter wire especially if it’s just for a few days like the op stated, I drove mine around for over a week without the instrument panel without issue. Saying that, the charge light does somewhat contribute to the regulation so I wouldn’t do it long term as you may damage the regulator. One other point, if you have the Nissan alternator, I have on my track car, it does need that exciter wire. I tried it without and it just wouldn’t regulate at all.

PaulD_944S2

You don't mention the model year of your car but if it is equipped with ABS or AIRBAGS then do not operate or start the engine without the IP.

Both of these systems will set fault lights when you re-install the IP becuase they monitor the condition of the warning light(s) in the IP.

MattSlay

It’s a 1990S2 with Air Bags.

rhis is good advise. I will be sure not to start the car then, because I do not want to deal with resetting the air bag warning light.

MAGK944

Good point, I only tried it on MY86 cars so ymmv.

marc abrams

Being stuck on the side of the road sucks. I really hated to post here but I do have a conscience if the OP got stuck and I knew something that could have prevented him from being stuck. Everything you just stated is incorrect. In my post I said "may not charge" and not "won't charge". Self exciting or the so called "one wire" alternators have been around for a long time in class 8 trucks and other heavy equipment. What makes a alternator self exciting? The internal voltage regulator. Around 1995-2000 voltage regulator manufacturers whether OEM or aftermarket, quietly made a change to the self exciting design. Infact the alternator you buy at your local Auto-Zone for your 1975 Impala is the same alternator you see in the Jegs catalogue as a "one wire alternator". So it can be hit or miss whether or not an alternator with self excite or not. How do I know all this, I worked in a auto electric shop part time rebuilding starters, alternators, and other stuff too along with my full time truck/heavy equipment mechanic job.
Once the alternator is putting out, you can remove the exciter circuit. It will not damage the alternator or voltage regulator or affect charging.
Some alternators require a separate 12 volt feed for voltage regulation. This is mostly on Ford's and GM alternators.
If you do a little research you will find that Porsche had TSB on the 928's not charging because of the charge light bulb.
And that's our science lesson for today kids.

MAGK944

Dude you need to chill, I was simply relating my experience and there is nothing “incorrect” about me stating that I drove around without an instrument panel in my 86 without any issues, it’s simply a fact, however ymmv.

Thanks for the lesson

PaulD_944S2

To MATTSLAY:

I would strongly suggest that you disconnect the battery before starting work (not for safety reasons, but airbag/ABS reset), and put a tag or note on the steering wheel not to start the car.

Very very cheap insurance!

BTDT!