Electrical issue

[bnc04]

Hi, My 88 has developed an electrical issue. The battery and Alt have tested out fine. The volt meter while running is in the 9-10 volt range. ( it used to be 11 or 12) It drops to 8 when I use the power windows. It seems to fluctuate a little higher and lower while driving. Sometimes when I apply the brakes the radio will stop playing for 5 seconds ( cd or radio) both do it. The windows go up and down pretty slowly and the idle seems to surge ever so slightly now. Where should I begin to look? Checking the grounds I will do this afternoon. Anything else? Thanks in advance,
Brett

 

[opfor2]

My 90 K-5 does something like that too, I have a new 200 amp Alt and when I run the AC and fan on high the volt meter drop's down to like 10 volts. You'ed think that with a 200 amp Alt that wouldn't happen.

Dan..

 

[cybrfire]

If the batt and alt are truly good then I would say start checking connections. You got something loose or corroded somewhere.

 

[zeroz400]

When your truck is running it should be in the 12-15 volts range. I would check you ground wires, they may be corroded or dirty. A battery is approx 12.6volts so if ur battery isn't that when you go to start it i would say the battery is the culprit.


Later

 

[BAJA_BLAZER]

I'll second that! Check/replace the ground leads.

 

[uao85]

use a bigger gauge wire running from your alt to your battery to let the juice flow back to the battery better. Helped for me.

Remington

 

[bigburban383]

The alternator test you did is obviously not right. A passing score would include 14-15 volts when the engine is running. Take it to a shop and they will put a load on the system to test the alternator and battery.