sergio620 Posted March 3, 2017 Report Share Posted March 3, 2017 Hello so when I turn on my headlights my radio shuts off the cluster lights dim very low and my headlights dim as well but when I turn the headliights off all power goes back to normal and everything lights up again any suggestions? Quote Link to comment
wayno Posted March 3, 2017 Report Share Posted March 3, 2017 Battery is getting low, is the alternator charging? 1 Quote Link to comment
datzenmike Posted March 3, 2017 Report Share Posted March 3, 2017 What year? Charge light come on at all? Does your battery go dead at all? Does the headlight fuse get hot to touch. I think it's the one closest to the driver. With the engine running you should have about 14 volts and over 30 amps of current available from a charging alternator. This should be more than enough to run everything even without a battery. With the engine running and the battery ground loosened at the battery. Just for a couple of seconds remove the ground wire from the battery..... (but put back on immediately after) Does the engine keep running? Turn on headlamps and try again. Does it keep running? 1 Quote Link to comment
sergio620 Posted March 3, 2017 Author Report Share Posted March 3, 2017 1979 all power is fine but when I turn on the headlights I see my radio shutoff and my dash lights go really dim and my headlights look really low too Quote Link to comment
wayno Posted March 3, 2017 Report Share Posted March 3, 2017 Here is the thing, my truck started when I finished a job one day, it was a long day and about half way home I had to turn on the headlights, my radio started cutting out a little while later, but if I turned the headlights off it was fine, luckily I made it home turning the headlights off when I could, the alternator had mostly quit charging and I was running off the battery with the headlights on, as long as I didn't have the headlights on I was good as long as the engine started right away. Modern radios cut out when the voltage gets below a certain point, dim headlights would confirm this, and if you turned the headlights off but left the park lights on, then the dash lights would get brighter when the headlights were turned off. Don't just assume that your charge system is good, check the voltage of the battery, then start it and see if it jumps to 14 volts, do the test Dmike mentioned, otherwise you will likely be on the side of the road very soon scratching your head wondering what the......................... Has it been turning over slower lately? Quote Link to comment
banzai510(hainz) Posted March 3, 2017 Report Share Posted March 3, 2017 All power is not fine!!!!!!!!!!!!!! does it do it when Heater on. Or get worse? hit break and lights dim even more. I believe the trucks all had 35amp alt so yours might be giving out get a cig lighter VOLT meter. sold on amazon and other places so you know whats its doing at different times. So you can monitor this.While driving. Can be corroded batter cables to a weak alternator, loose belt ect....... Quote Link to comment
sergio620 Posted March 3, 2017 Author Report Share Posted March 3, 2017 So I had a snapped alternator belt but previous owner swapped over a s10 alternator on it so what size belt should I get? I bought a stock 620 one but it feels too short Quote Link to comment
banzai510(hainz) Posted March 3, 2017 Report Share Posted March 3, 2017 the store can tell you the size of the stock one in mm. so you got to figure what you need to add. Most are in 5mm increments. belt must be really bad to snap. I never snapped one. a s10 alt should be more than enough amps to power a 620 Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.