1990 Blinker Problem

I have a 1990 GP with 18k miles. The problem I am seeing is that when either blinker is activated the voltage gauge starts to flutter and bounce between ~ 13 and 17 volts. This seems to be the only condition that causes the failure. I recently replaced the alternator and it failed shortly after this started happening. Could it be the blinker module / swithch? Any ideas would be appreciated??

BTW, I just replaced the battery and the alternator.

the turn signal switches are a common problem on these cars, not a daunting task, but a little frustrating while re-routing the wires down the steering column. One word of note, if you have a Haynes repair manual, it fails to tell you that you have to remove the bolt in the center of the wiring junction where the turn signal switch plugs into the car. It looks like it just pops off toward the drivers side of the car, but it actually separates toward the passenger side, after separating the junction block by removing the bolt in the center.

18k on your 90 gp ? too cool My 90 gpse has 180k and still going strong :) I had similar prob awhile back but mine would do 15 and drop to 9 volt then peak back at14/15 volt new alt and battery (and cleaned all ground connects) helped for about 2 months now it is starting to fluctuate again especially if brake is held or turn sigs are on,I know it will drop a bit but at night it looks like I'm flashing lights .
Hope you find solution If i find answer i will let you know, So far I just chalk it up to age of car
peace

the turn signal switches are a common problem on these cars, not a daunting task, but a little frustrating while re-routing the wires down the steering column. One word of note, if you have a Haynes repair manual, it fails to tell you that you have to remove the bolt in the center of the wiring junction where the turn signal switch plugs into the car. It looks like it just pops off toward the drivers side of the car, but it actually separates toward the passenger side, after separating the junction block by removing the bolt in the center.

So would a faulty switch cause this type of voltage fluctuation? I will look in my haynes to find its location.

Thanks

yes it will, as it draws more amps than it should. The other thing to check is all your electrical connections, battery cables, underhood battery terminal and the underhood relay center for corrosion. Fluctuations in voltage when an accessory is activated normally indicate a bad ground or excessive draw.

yes it will, as it draws more amps than it should. The other thing to check is all your electrical connections, battery cables, underhood battery terminal and the underhood relay center for corrosion. Fluctuations in voltage when an accessory is activated normally indicate a bad ground or excessive draw.

Thanks, I will give all the connections and grounds the once over when I get some free time, and will also check the junction box and the computer connections.