On my 1982 which has been running fine, all electronics, accessories, etc. all of a sudden today it just went full right (clockwise). Any ideas as to cause, correction? I am guessing my alternator has gone as well. Voltage meter was not showing its normal reading (right side of straight up). Wondered if it was simply running off the battery. Unplugged the battery with car running and engine died so I'm guessing no output from alternator.

Anyone have any ideas or suggestions? I don't have a voltage meter that will measure 13-15 volts (only goes to 10v). I'll run it by Advance Auto Parts tomorrow and let them test the alternator but, assuming I'm right, guess it's just one of those things......they fail without notice.

Thanks, Mark

 

i've had failure on my '79 of some of the gauges not all at once so not sure about it being the alternator, it sound like you've lost ground to your cluster though, check your wires from your alternator the best you can for bad connections or wire that rubbed until it arc'd possibly. thier is a board for the instrument cluster and also one for the tach, if both tach and gauges aren't working i'd suspect it was in wiring or alternator..if one or the other is working then it could be the circuit board or wire feeding the board, or the plug that plugs into the board may be corroded/green...i did have to run a new ground to my tach because i lost ground to it. never did find the problem as it was a maze of wires in a tight spot at the fuse box.
take your alternator to a competent alternator repair shop to be checked, or get a 2nd & 3rd opinion if you use a franchise, their people usually aren't competent enough to reboot a computer much less hook up an alternator properly for diagnostics. Have the alternator shop rebuild yours if its defective, those rebuilders down in mexico that work for the franchises have a high rate of return for re-repair

 

Thanks. Nope, it's only the tach (as far as gauges). Just seems odd that my alternator AND tach seem to be going at basically the same time. Did not know if maybe the tach received its info from the alternator. It's Delco-Remy alternator so would like to keep it or replace it with same.

Tach, from what I've read most common problem is the circuit board. I'll pull it out tomorrow and see what I can see. There's a local place here in Atlanta that sells them so easy to replace.

Thanks.

 

yes pull your tach and speedo out and hook 12v direct to the distribution panel where hot & ground of the plug clips in, make sure you follow your diagram to the tach for your positive connection..if it tests ok your tach will auto calibrate to zero,that means you have a fault in your wire or plug from the fuse area, if it doesn't zero follow your wiring diagram to back of tach itself and tie into the circuit board pos to pos, neg to neg and if it zeros then you have a bad connection in your distribution panel somewhere, possibly corrosion/green,or a break.your ground on the circuit board will be the one that goes to all the bulbs etc,don't hook it up backwards by accident.you can also smell your circuit board for the smell of burned circuits..if you've never pulled the tach/speedo assembly out before,"its s tight spot"but on my
'79 the speedo cable pops right out by pressing a tab, it snaps back in just as easy.the plug for your tach has a tab and it pulls right out yours is probably the same setup as mine if its mechanical speedo, circuited tach.You can't use anything but your year car circuit boards, its a slightly different board calibrated differently. I bought from last detail in georgia, one piece i got was actual factory GM and the other was aftermarket, all worked well...the manufacturer of the aftermarket had a note: not to buy any boards from china as they aren't calibrated properly etc...keep that in mind

 

That's what I'd be looking at first...