ALT light when selecting reverse

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patrickdotryan
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ALT light when selecting reverse

Post by patrickdotryan »

Hi Guys and Gals,

All has been going well until this morning. Truck starts and runs fine. Headlights, taillights and brake lights work fine too. However, When I put the truck in reverse, the backup lights have stopped working and I get a solid ALT light. Just in reverse. And driving to work I notced that also when I put the blinkers on, I get a very soft ALT light blinking and NO BLINKERS, which is very confusing to the others on the road :D For reference, the truck is idling fine, it's not one of those "low idle, alternator can't keep up with the equipment" type ALT light indications. It's like, as soon as I shift into reverse, the ALT light comes on strong. The blinker variation is weaker and flashing, but happens even at road speed.

In general my wiring is pretty clean and stock, I've pulled off anything extraneous over the years. There don't seem to be any obvious loose wires or anything. Electrical issues are not my jam!

Thanks,
Patrick in San Diego
1971 F250 Custom
Camper Special
Prairie Yellow
390 (was a 360), C6 Auto, Dana 60
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Ranchero50
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Re: ALT light when selecting reverse

Post by Ranchero50 »

Sounds like your backup circuit has shorted out. Not sure on the blinkers.
'70 F-350 CS Cummins 6BT 10klb truck 64k mile Bahama Blue

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patrickdotryan
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Re: ALT light when selecting reverse

Post by patrickdotryan »

Thanks Ranchero50. Seems that way but weird that it is both blinkers and reverse lights. Maybe something in the steering column since they both go there? Funny enough right now it's not happening so I'm guessing it's gonna be a little hard to track down. :hmm:
1971 F250 Custom
Camper Special
Prairie Yellow
390 (was a 360), C6 Auto, Dana 60
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KRob
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Re: ALT light when selecting reverse

Post by KRob »

Check the switch for reverse on your truck. I know on my truck, which has a manual 5 speed, when i installed extra reverse lights it pulled to much juice through the switch and burned it out. Quick easy check and fix.
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