it all started today when i winned out my engine at about 110mph, i had my lights on and as soon as i starting winning and backed down to 70 my volt gauge started bouncing back and forth like crazy between 11 and 14. as soon as i turned my lights off it went back to its normal 13.5 or so. i turned the lights back on and the needle drops to 11 then back up to like 12.5 for about 2 seconds then starts bouncing again. any suggestions on this?
voltage going crazy
- Thread starter 19mustang65
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reenmachine
Dirt-Old 20+Year Member
Drive with your lights off.
Just kidding. Do you drive like that often, or is that a rare occurance? Just wondering if the problem cropping up just then was a coincidence or directly related to spinning the engine up. Check your alternator for proper operation, and check out the voltage regulator as well -- I've seen them cause some pretty bizarre problems.
Is it directly from activating the lights, or just from increased electrical load? Power up the stereo or wipers or something and see what the gauge does.
Just kidding. Do you drive like that often, or is that a rare occurance? Just wondering if the problem cropping up just then was a coincidence or directly related to spinning the engine up. Check your alternator for proper operation, and check out the voltage regulator as well -- I've seen them cause some pretty bizarre problems.
Is it directly from activating the lights, or just from increased electrical load? Power up the stereo or wipers or something and see what the gauge does.
WORTH
Dirt-Old 20+Year Member
the headlight switch has a circuit breaker built into it, it more than likely has a short in the headlight circuit and the breaker is turning the lights on and off. unplug the bulbs first and see if the short is still there, then trace out the wireing.
WORTH
Dirt-Old 20+Year Member
19mustang65 said:
Yes if you buy a new switch it should be capable of halogen lights, I had to replace mine in the 70 ragtop because the old one couldnt handle the halogens.
Relays...
Just get some relays for your headlights. That way you can run better headlights than stock. Does your voltage drop to 12 at idle (w/headlights on) and go to 14 when you step on the gas? If it does, your alternator does not put out enough current at idle. This is not really a problem as the alternator will catch up while you are driving. I rewired my headlights with new wires and relays, upgraded to H4 bulbs, my headlights are 10x better now. Before I rewired them (just had the higher wattage bulbs), they started doing the flash on and off thing. After I put in the relays they worked perfect.
Just get some relays for your headlights. That way you can run better headlights than stock. Does your voltage drop to 12 at idle (w/headlights on) and go to 14 when you step on the gas? If it does, your alternator does not put out enough current at idle. This is not really a problem as the alternator will catch up while you are driving. I rewired my headlights with new wires and relays, upgraded to H4 bulbs, my headlights are 10x better now. Before I rewired them (just had the higher wattage bulbs), they started doing the flash on and off thing. After I put in the relays they worked perfect.
WORTH
Dirt-Old 20+Year Member
19mustang65 said:
You shouldn't need the relay setup with the new switch, and low charge at idle is not a problem unless you spend all day idling.
You fixed it with the switch.
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