92 f150 4.9

tumblemoose · Jul 31, 2008

Battery cables were corroded at the terminals, cleaned em up. Finally started after a jump.

I noticed the voltmeter on the dash was waving wildly back and forth towards 18, the engine idle was normal.

Decided to put a load on, so I fired up the A/C and turned the fan on. Gauge steadied and went to center. Later that day the truck started fine but still had the wavering vm. Went out today - the battery is dead again and it would not start.

Could anyone please narrow this down for me?

armykuwait0506 · Aug 22, 2008

tumblemoose said:
Battery cables were corroded at the terminals, cleaned em up. Finally started after a jump.

I noticed the voltmeter on the dash was waving wildly back and forth towards 18, the engine idle was normal.

Decided to put a load on, so I fired up the A/C and turned the fan on. Gauge steadied and went to center. Later that day the truck started fine but still had the wavering vm. Went out today - the battery is dead again and it would not start.

Could anyone please narrow this down for me?

not too sure but could be the alternator maybe the voltage regulator went bad and its makin it spike like that take that in to autozone or a parts store and they can test it for you other than that im not too sure

James Hengl · Jan 6, 2009

Check your fuse box for blown fuses and also check to see if something is drawing power will the truck is shut off if so follow the wiring back to the source of the problem. also check to see if something is turning its on at night it can happen with if something is shorting out. be careful not short out the voltmeter.

1992F250 · Feb 27, 2009

Check the out put at the terminals from the Alternater/Generator (forgive the spelling) to see if it's acting the same as the gauge. The two problems may not be related.