98 C1500 5.7 Turn Signals Fast

[Sean Sills]

Both of my turn signals just stared flashing really fast. I checked and didn't find a bulb out. My voltage on my dash just started to drop when turning on the a/c. Turn a/c off and voltage returns.

 

[GoToGuy]

At idle or 2000 rpm voltage drop.. Get out voltmeter check Alt output . Clean grounds?

 

[jd33173]

check your alternator - should be pumping 14.5v with the a/c off and about 13.5 with the a/c on. Also get a load test on the battery as if the internal resistance on the battery is too high, the alternator can be fine but will not be able to charge it.

 

[Sean Sills]

At idle or 2000 rpm voltage drop.. Get out voltmeter check Alt output . Clean grounds?

Idle

 

[GoToGuy]

There's going be drop as the compressor mag clutch kicks in. Does the out put recover at 1500, to 2000 rpm simulate cruise rpm? Right off the alt output term should be 14 plus volts.
Turn signals, what about front bulbs? Check the ground at rear frame, clean tight. Have installed led taillights? Failed turn signal flasher?

 

[Sean Sills]

Oh I'm basically at 14.5 until air turns on high and then drops to 10.4 and a high pitched squel when air on high.

 

[Sean Sills]

Oh I'm basically at 14.5 until air turns on high and then drops to 10.4 and a high pitched squel when air on high.

I just had the top pulley replaced maybe 200 miles ago.

 

[Schurkey]

Oh I'm basically at 14.5 until air turns on high and then drops to 10.4 and a high pitched squel when air on high.

10.4 volts is WAY too low.

Severe charging-system problems which may or may not include a worn-out belt, worn-out belt tensioner, (squealing belt) or internal alternator issues causing squeal. Outside chance of a locked-up A/C compressor, but that would tend to stall the engine rather than just reduce RPM and therefore alternator output.

Get the vehicle voltage back where it should be, and see if the turn signal problem resolves itself. Best guess is that there's something else wrong with the turn signals, but you can hope for the best.

 

[Sean Sills]

10.4 volts is WAY too low.

Severe charging-system problems which may or may not include a worn-out belt, worn-out belt tensioner, (squealing belt) or internal alternator issues causing squeal. Outside chance of a locked-up A/C compressor, but that would tend to stall the engine rather than just reduce RPM and therefore alternator output.

Get the vehicle voltage back where it should be, and see if the turn signal problem resolves itself. Best guess is that there's something else wrong with the turn signals, but you can hope for the best.

I will give it a try.