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#26 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
I just checked the voltage on my battery. I have 13.15V and it will take 3 amps. I worried about overcharging. If my battery read 13.15V and is still taking 3 amps is that a sign of a bad battery? The top of the battery looks a bit moist around the positive post.
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Photo Gallery of 1972 K/5 Blazer CST Last edited by Green Monster; 09-19-2007 at 08:35 PM. |
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#27 |
Registered User
Join Date: Mar 2005
Location: Claremore, OK
Posts: 486
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Re: Both headlights burned out tonight... Why?
When I mentioned that I replaced the dimmer switch and external volt reg....I had replaced my 2nd new battery just a couple days before my blow out...I guess the regulator had been toasting them too, wouldn't hold a charge.....Same thing for you maybe?
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93 Sonoma 2.8/5spd 75 Malibu Classic 350/350 If it don't have round headlights and a carb, I don't trust it! Last edited by jrb71c20; 09-19-2007 at 09:53 PM. |
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#28 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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Re: Both headlights burned out tonight... Why?
Here is a quick way to see if you have a drain on battery.
1--remove ground cable 2--hook test light between cable and ground 3--if light glows you have a drain 3--pull one fuse at a time until light goes out 4--when it goes out , that is the circuit your drain is on 5--if it does not go out after tesing each fuse remove , remove the plug on voltage regulator 6--if it goes out replace regulator 7--if it stays on remove all wires from alt. 8--if it goes out replace or repair alt. 9--That should help narrow it down as the wire that runs back to battery juction post is ok because it is not blowing your fuseable link. 10--(above advice carries no warrenty or guarantee)
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56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer |
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#29 |
Registered User
Join Date: May 2007
Location: texas
Posts: 329
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Re: Both headlights burned out tonight... Why?
Taking 3 amps. is normal. It will never drop down to 0. But if you have 13 volts, go ahead & remove the charger, let it set overnight & see if you still have 13 volts. You will get vapor out the top vents, so don't worry about the top of it being moist. Just wipe it off with a paper towel, But beware, it is acid. There's no special way that batteries drop dead. Usually they go out kinda slow, but unnoticed. So could have been on the downward slide for awhile. But if it holds 13 volts overnight, I'd give it another try before replacing it. Just carry jumpers in case. jhow has good advise. I'm trying to keep it simple. I really think you're making more out of it than it is. If it were mine. I'd simply drop in a new voltage regulator, and couple headlights and call it a day. If I noticed the starter turning slow, especiely after a warm start Like after you shut down & restart about 1 hour later, I'd replace the battery. It's that simple. That's what I would do if mine did what yours had done. But it's your truck so do what you feel comfy with. If it has anymore problems after doing that, we'll take it from there. But have to start somewhere. Their's lots of good people on here who's willing to help you out.
Last edited by old man jimmy; 09-20-2007 at 02:49 AM. |
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#30 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
Thanks guys. I'm have been swamped with work this week. I just have not had time to work on it yet. I'm just trying to collect enough information to get the job done correctly and quickly when I can find time to work on it Friday afternoon or this weekend. I will let you know how I make out.
That step by step list is fantastic. Thanks Jhow66! BTW- I want to make sure I do this right. I really would hate to lose this Blazer in a CAR-B-Q blaze.
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Photo Gallery of 1972 K/5 Blazer CST Last edited by Green Monster; 09-20-2007 at 08:45 PM. |
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#31 | |
Post Whore
![]() Join Date: Feb 2000
Location: Rose Hill, KS, USA
Posts: 12,684
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Re: Both headlights burned out tonight... Why?
Quote:
![]() Seriously, while you are taking care of this problem it sure wouldn't hurt to have your shop fire extinquisher (which we all have I hope) handy and I would also consider keeping the positive battery cable loose enough that you can yank it off if you run into a problem. Back before I tore my K20 apart I was tracking down an electrical problem and I watched one of the engine bay harness go up in smoke from the battery to the alternator - happened so fast I couldn't even think what to do. I was just lucky nothing started flaming.
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1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14 |
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#32 |
Senior Member
Join Date: Aug 2005
Location: OKC, OK
Posts: 2,365
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Re: Both headlights burned out tonight... Why?
A drained battery is another symptom of a bad regulator. The regulator is shorted internally drawing power off the battery. I would definitely install relays on your headlights before I put those lights back in it.
Mike
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Mike Redpath |
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#33 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
How would the relays for headlights be set up?
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#34 |
Senior Member
![]() Join Date: May 2006
Location: Philadelphia, Pa. 19454
Posts: 9,516
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Re: Both headlights burned out tonight... Why?
VinceY just wrote up a good thread pertaining to that very topic, 1 page back... J.
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Semper Fi...Uncle Sam, you da man All parts offered to help are free, unless otherwise noted Dont try this stuff in my build thread, unless you have 55 years of mechanical OTJ training SAFETY FIRST AS usual, off topic They say your mind goes second, can't remember the first Jim |
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#35 |
Senior Member
Join Date: Jan 2005
Location: Raleigh, NC
Posts: 894
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Re: Both headlights burned out tonight... Why?
The relay mod is great IMO but it would not have saved your headlights anyway with a regulator failure. The entire electrical system voltage went up and it still would have toasted the headlights. If anything the factory wiring would have served to help save them since the resistance is so much greater going through the entire wiring harness as OEM and the voltage drop across that would have lessened the voltage getting to the bulbs. Switching to the relay mod would have served to deliver nearly 100% full charging voltage from the alternator straight to the headlights.
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#36 | |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
Quote:
I finally found some time to perform some testing. I found that I have 12.15V being drawn from my ground cable. 1. I pulled every fuse, one at a time. I had a draw of 12.15V every time. 2. I disconnected all the wires at my fuse block. Still 12.15V being drawn from the ground wire of the battery. 3. I unplugged my voltage regulator. Still 12.15V being drawn from the ground wire of the battery. 4. I disconnected all wires from my alternator. Still 12.15V being drawn from the ground wire of the battery. . 5. I unplugged my dimmer switch. Still 12.15V being drawn from the ground wire of the battery. I have run out of time this morning. What should I do next when time permits further investigation?
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Photo Gallery of 1972 K/5 Blazer CST Last edited by Green Monster; 09-23-2007 at 10:13 AM. |
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#37 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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Re: Both headlights burned out tonight... Why?
Boy you are trying to make things hard!
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56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer |
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#38 |
Registered User
Join Date: May 2007
Location: texas
Posts: 329
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Re: Both headlights burned out tonight... Why?
I give up...
Last edited by old man jimmy; 09-24-2007 at 01:06 AM. |
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#39 | |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
Quote:
I know some harness should be fried... that's why the battery has been disconnected.
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#40 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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Re: Both headlights burned out tonight... Why?
Are you checking it this way?
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56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer |
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#41 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
Yes. That is how I'm testing. Is that right or wrong?
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#42 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
I connected my battery cables. I then tested each fuse to see if I had any current passing through them. No current passed through the fuses. I pulled my hazard switch and tested that fuse. I got 11V.
I saw my under dash lights were lit so I figured I must previously tested for current on the ground cable with the door open. So I made sure I closed the door and the key was off (it has been off throughout this entire trouble shooting process). I disconnected the ground cable and bridged the ground cable to the battery with my meter. Still pulling 12V. This is maddening. Could the memory from my radio pull 12V? That is the only thing that should be pulling any electricity.
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Photo Gallery of 1972 K/5 Blazer CST Last edited by Green Monster; 09-24-2007 at 07:08 PM. |
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#43 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
Could my ignition switch be bad? Is there any reason my gas gauge should be reading an inch and a half past full now? It worked perfectly before this electrical issue. Any help beyond this point would be appreciated.
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Photo Gallery of 1972 K/5 Blazer CST Last edited by Green Monster; 09-24-2007 at 07:46 PM. |
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#44 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
Just to be sure... I disconnected my voltage regulator and alternator while the doors were shut. Nothing should pull electricity except my radio. I'm still having a draw of 12V.
Could someone please test this theory? Is a 12V draw from the negative post to the ground cable normal?
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#45 |
Senior Member
![]() Join Date: May 2006
Location: Philadelphia, Pa. 19454
Posts: 9,516
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Re: Both headlights burned out tonight... Why?
Maybe you melted a wire inside your harness before the lights blew, but I think the fusible link would have melted first. Electrical problems are second on my hate list, rust is first
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Semper Fi...Uncle Sam, you da man All parts offered to help are free, unless otherwise noted Dont try this stuff in my build thread, unless you have 55 years of mechanical OTJ training SAFETY FIRST AS usual, off topic They say your mind goes second, can't remember the first Jim |
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#46 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
Looks like I have to call a flatbed and have it towed to a automotive electric shop to get this thing fixed.
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#47 |
A guy with a truck
Join Date: Sep 2005
Location: Germany, for now
Posts: 5,920
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Re: Both headlights burned out tonight... Why?
Test for amperage draw, not voltage. Everything will be 12V. Disconnect the stereo and try again. You have the fundamentals down- you just need to spend a little more time with it.
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#48 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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Re: Both headlights burned out tonight... Why?
That's the way to check it. Get the battery to full charge like someone else said and remove cables overnight. If it is down the next morning, you have a cell in the battery shorting out . Try another battery before going further as a short in the battery will cause a voltage spike that could cause your headlights to blow.
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56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer |
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#49 | |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
Quote:
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#50 |
Registered User
Join Date: Mar 2006
Location: Malvern, PA
Posts: 951
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Re: Both headlights burned out tonight... Why?
I attempted to check for amperage draw yesterday. I was thinking the same thing. The meter was not showing anything. I'm not too sure why it was not registering a reading. I'll try again this afternoon.
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Photo Gallery of 1972 K/5 Blazer CST Last edited by Green Monster; 09-25-2007 at 03:40 PM. |
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