LUVTruck.com

electrical shit...love this. My alt. light turned on today and man it pissed me off...i just replaced the alt. last week with a 50 amp stock replacement. The alt light now comes on real bright and my headlights dont work unless the truck is running. I dont get it...the electric fuel pump kicks on and it turns over but no headlights...any ideas?

Check the connections on the new alternator, might be one wiggled loose in the swap. I had it happen on my 79 just the other day actually, though it was months after I had swapped alts. I noticed a wire dangling just before I was about to take it on a fairly long drive too, lucky for me.

After that, the voltage reg is the other part of that equation. I try to replace both together when I can afford it just so I have all new parts. The alt and the reg together can be a bit steep though. My last alt/reg problem turned out to be the reg. It would work ok sometimes, others it stuck. A sharp rap with a screwdriver handle and it would go back to working again for a while.

You might also check the wiring at the battery, especially the smaller wire going to the positive. A loose connection there might cause things to get screwy. Headlights working only when the truck is running sounds like the typical "ghost in the machine" electrical gremlin you get from a short, loose wire, loose ground, etc. The battery is the place to start tracking those down.

it,s better to replace the reg and alt at the same time. i only replace the alt and it gave out after a week. i then replaced the reg and alt and have not had a problem since.

Nate

Does the battery seem to holding it's charge? Put a multimeter across the battery posts on the appropriate polarity and DC voltage scale. Read the voltage with the truck turned off. Then read it again with the truck running. Voltage should've increased 1 to 2 volts. Look close. If the voltage doesn't increase, you've got a charging problen like the Alt. warning lite is telling you.

yeah i have the same problem sometimes the alt light comes on and then it turns off and some times it stays on and goes dead. at first i could tap the regulater and the light would turn off, but not any more dangit.

Mad4Dirt

When I've had that happen in the past, it's invariably been burnt points on the relays in the voltage regulator. Files are available to dress up the burnt points, but I've never found that to be a long term fix. I always ended up replacing the voltage regulator.

arighty i'll take ur word for it im heading up to napa right now.
Thanks For the help
Derrik

I tried the old file and readjust on the reg and got another week without a problem. I think the replacement regs out there just are not meant to be worked on. I still have a couple of older ones (look old enough to have come on the truck) I keep meaning to crack open and check out to see if they are more able to be rehabilitated.

Read my lips. Get new battery terminals. My truck was doing the same thing up until I put new battery terminals on it.

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- 1976 Chevy Longbed - Daily Driver
- 1981 Chevy Shortbed 4X4 - Needs Help!
- 1981 Chevy Luv 4X4 - Newly put together

I think the Regulator on my Luv may be the factory one. One I bought it was missing the Altenator. I dont seem to have a problem chargeing, but was wondering how long a regulator life span lasts? Also what amp range do the alts put out?

ZANE

The average alternator has a 50 Amp max output, and I've had those old voltage regulators work for 20 years. But like I said in another post, I've learned to just chuck 'em when they go bad and buy another.

I do believe I have seen somewhere that the stock LUV alt. puts out between 35 and 45 amps.

My little bookie here says it ranges from 25 to 45, so I think 30 to 50 would be a good range.

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More LUV than one man could ever need - Spread the LUV!
- 1976 Chevy Longbed - Daily Driver
- 1981 Chevy Shortbed 4X4 - Needs Help!
- 1981 Chevy Luv 4X4 - Newly put together