calling all electrical gurus!! Frustrated and need help!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jorgensensc · 11-30-2004, 01:49 PM

So I've been hunting down an annoying problem with my truck. I was having major issues with the truck not starting, then changing something out and it would start, then it wouldn't start a day later. To date I have replaced the battery (new optima), the alternator (new), the starter (known good), timing chain (it was a shot in the dark), and the distributor (known good). I thought I had the problem solved finally. The truck ran great for a few days, then when I went out to go start it the battery was dead, again. I checked a couple of things and this is what I came up with:
The alternator puts out 14.5 volts, at the back of the alternator, but I only get 13.6 at the battery.
When I run a multimeter between the negative post and the negative cable I get a 3.5 amp draw. (today, 2 days ago it was a 2.5 amp draw). I narrowed it down to the ignition fuse. When I take that one out, all the draw goes away. I pulled the distributor feed, still had the draw. I pulled the ignition switch feed, and still have the draw.
Where else should I look for the draw on the ignition feed? I can't seem to find the source of the pull?
I am running a remote starter solonoid for the starter (it was a cure for a previously thought starter heat soak issue, which actually wasn't a problem at all), but it doesn't appear to be the culprit either.
Please, any and all advice would be greatly appreciated. Thanks in advance!
Shawn

jhow66 · 11-30-2004, 01:57 PM

Unhook voltage regulator and check.

jorgensensc · 11-30-2004, 02:03 PM

Thanks for the response. I guess I forgot to mention it is an internal voltage regulator alternator.

JimKshortstep4x4 · 11-30-2004, 02:08 PM

Have you tried disconnecting the alternator to see if the draw goes away?
Depending on it is wired in you can have a draw problem that can be fixed with a diode.

Jim

68speedalert · 11-30-2004, 03:01 PM

After the truck has sat a few hours, enough for the engine and body to be cool, lay your hands on stuff and do the temp test. For instance, the alternator iis likely the cause. Lay your hand on it. If it's warmer than the surrounding engine, that's your problem. If not, start feeling anything electrical possibly on that circuit, including the ign switch.

sneakysnake · 11-30-2004, 04:02 PM

http://67-72chevytrucks.com/vboard/s....php3?t=129594

will help you track down the short

meathead95 · 11-30-2004, 06:33 PM

what about your neutral safety switch? if you dont have it all the way in park or the switch is wearing out that could cause it not to crank over all the time

chickenwing · 11-30-2004, 07:16 PM

Quote:

Originally Posted by jorgensensc

I narrowed it down to the ignition fuse. When I take that one out, all the draw goes away. I pulled the distributor feed, still had the draw. I pulled the ignition switch feed, and still have the draw.
Where else should I look for the draw on the ignition feed?
Shawn

Narrowed down Shawns words. What all draws power from the ign fuse? I can't read the diagram posted on the board. The fuse block pictured is lousy. Will look at mine when I get home if no one post.

tom hand · 11-30-2004, 07:28 PM

Are you doing the test with the key off? The ignition fuse should have no draw with the key off...regardless of what is hooked to it

chickenwing · 11-30-2004, 07:36 PM

That makes since. So, with that tidbit of information... He says the draw is still there with the ign switch connector pulled off. Is there something slagged either behind the fuse panel or in the connector?

chickenwing · 11-30-2004, 07:43 PM

If I am reading the posted diagram right the ign fuse draws power from the ign switch. It is not bussed. Looks like power runs from the ign switch to a splice. 1 part of the splice goes to the coil other part to ign fuse wich then goes to the fuel gauge feed on the instrument connector.

68speedalert · 11-30-2004, 08:04 PM

Good job chikenwing. With the key off it shouldn't matter if the ignition fuse is in or out. There shouldn't be any voltage there.

Sounds like and ignition SWITCH is the problem.

chickenwing · 11-30-2004, 08:30 PM

Don't be too fast on the kudos. Could be 1 or more bugs in there. Double check this checking for coil power with key off. Would the fuel gauge and coil burn up enough to kill a battery so fast? Hope I'm helpin.

Longhorn Man · 11-30-2004, 09:27 PM

yes, a powered coil would drain the battery, quicker than that IMO. However, he unplugged it and the amp draw remained the same, so that is not the problem.
If it was the problem, his coil would have burned up by now too.

Don Smith · 11-30-2004, 10:40 PM

I had a intermittent sticking anti-dieseling solenoid the caused similar problems. The solenoid is usually located just below and to right of radio under the dash.

mr402 · 11-30-2004, 11:43 PM

Place to start would be to see what fuses are hot with the ignition off. Should be an easy check with a voltmeter. There is also a tap or two on the fuse box that are not fused and are hot all the time. Put your amp meter back on the battery and pull just the hot fuses one at a time until you find the one that causes the current to drop. If you don't find it that way check the wires that plug directly into the fuse box and pull them one at a time. Things that come to my mind are the lighter, dome light and headlight switch. If you have a clock or stereo w/secondary wire to keep the clock/memory alive they should be checked as well. Good Luck! Finding them can be a $itch

chickenwing · 11-30-2004, 11:52 PM

I like a good puzzle. On someone else's truck. Will be real interested to find out what the bug is. When I get home I'm gonna trace it out on my diagram. There has to be some more items on the circuit. If there is no other components the only thing left is the wire itself and the fuse box.

chickenwing · 12-01-2004, 02:25 AM

OK. Went home and pulled out my old harness. The ign fuse IS fed from the ign switch. The ign fuse powers pin 3 of the cluster connector wich feeds the fuel gauge. There are 2 taps immediately below the ign fuse on the block. These are unfused accessory taps fed by the same ign switch wire to the ign fuse. There is a splice before the fuse that feeds the coil.

With the key off, there should be no power to the ign fuse. PERIOD. If there is the switch is likely bad. The nearest terminal on the back of the block is the reverse light fuse. I doubt it is arcing over to the ign fuse.
If you can pull your ign switch connector and there IS power on the ign fuse. Disconnect the battery, find the pink wire from the engine bay connector, trace it back and ensure there has been no arcing all the way to the coil. No find there, pull the fuse block in the cab and trace the 12gauge pink wire back till you see what has arced/melted over to it. The pink wire will lead from the fuse to a splice, the splice will lead to the ign switch connector and to the inside half of the bulkhead connector.

Hope this helps. If you need pictures I can provide but it will be tomarrow evening before I can.
Rich

Don Smith · 12-01-2004, 11:54 AM

In my previous post to this thread I said anti-dieseling Solenoid, I ment to say Relay.

jorgensensc · 12-02-2004, 11:27 AM

Sorry I haven't posted since posting this question guys. Work came up and I haven't been off until this morning (24 hour shift). Thanks for all of the great posts! I will work on it this afternoon after I get a little sleep and post what I find.
Chickenwing,
Thank you for the in depth trace of the wiring! I will look at that this afternoon. My guess is something has to be arcing, I because I just can't figure out how the coil and the ignition switch can both be pulled, and the battery cstill pull the amps, when I know the culprit is on the ignition fuse line somewhere.
I will give an update in a little while.
Shawn

chickenwing · 12-02-2004, 11:41 AM

...hmmm Whatever accesories you have plugged into the 2 taps below the ign fuse would be able to draw the power.

jorgensensc · 12-03-2004, 04:22 PM

O.K.
I found the problem, but I don't know exactly what to do about it.
I unplugged and checked wires all over the truck, then I came to the gauge cluster.
I unplugged it and the draw went away. Great!! I found it!!!
Then I tried to narrow it down. I undid the posts for the temp gauge and the draw went from 2.6 to 1.8. Next I undid the post for the fuel gauge and the draw went down to .01. Perfect!!! but now how do I fix the problem? Both gauges work perfectly. Is it possible that both of the resistor things on the back went bad at the same time? Could they create the problem? Any help would be appreciated!
Shawn

chickenwing · 12-03-2004, 04:30 PM

Now was that with the key off or on?

jorgensensc · 12-03-2004, 04:34 PM

key was off.

chickenwing · 12-03-2004, 04:59 PM

The way I see it you need to figure out where the power is coming from.

That circuit should have no power with the key off.

Those 2 items are supposed to draw power. 1.8 ohms or amps would be in range for a gas gauge, means you are sittin on E baby. 0-90 ohm sweep on the fuel sender. Dunno on the temp. But sounds reasonable.

You need to figure out where the power is bleeding over from. I know I am asking qestions over again. But I am not there. You sure the power is still there with ignition switch connector pulled off the switch? If it is and it it is not there when you pull the cluster connector, maybe something is bleeding over from the printed circuit board. Take a voltmeter to each pin on the instrument connector and find out wich pin has the voltage on it.

11-30-2004, 01:49 PM	#1
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	calling all electrical gurus!! Frustrated and need help!! So I've been hunting down an annoying problem with my truck. I was having major issues with the truck not starting, then changing something out and it would start, then it wouldn't start a day later. To date I have replaced the battery (new optima), the alternator (new), the starter (known good), timing chain (it was a shot in the dark), and the distributor (known good). I thought I had the problem solved finally. The truck ran great for a few days, then when I went out to go start it the battery was dead, again. I checked a couple of things and this is what I came up with: The alternator puts out 14.5 volts, at the back of the alternator, but I only get 13.6 at the battery. When I run a multimeter between the negative post and the negative cable I get a 3.5 amp draw. (today, 2 days ago it was a 2.5 amp draw). I narrowed it down to the ignition fuse. When I take that one out, all the draw goes away. I pulled the distributor feed, still had the draw. I pulled the ignition switch feed, and still have the draw. Where else should I look for the draw on the ignition feed? I can't seem to find the source of the pull? I am running a remote starter solonoid for the starter (it was a cure for a previously thought starter heat soak issue, which actually wasn't a problem at all), but it doesn't appear to be the culprit either. Please, any and all advice would be greatly appreciated. Thanks in advance! Shawn __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

11-30-2004, 01:57 PM	#2
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Unhook voltage regulator and check. __________________ 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

11-30-2004, 02:03 PM	#3
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	Thanks for the response. I guess I forgot to mention it is an internal voltage regulator alternator. __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

11-30-2004, 03:01 PM	#5
68speedalert Semi-Senior Member Join Date: Feb 2003 Location: Washington, MO Posts: 390	After the truck has sat a few hours, enough for the engine and body to be cool, lay your hands on stuff and do the temp test. For instance, the alternator iis likely the cause. Lay your hand on it. If it's warmer than the surrounding engine, that's your problem. If not, start feeling anything electrical possibly on that circuit, including the ign switch. __________________ '68 50th Anniversery LWB Custom Fleetside, '77 305 v-8, turbo 350, factory speed alert (still works), '71 drivetrain w/front discs. Some call it ugly yellow, others call it Ochre '83 Jeep CJ-7, <80,000 miles, original owner '04 Chevy Suburban, 4x4, 2500, 6.0 ltr, Predator Diablo programmer '95 GMC K1500 Extended cab

11-30-2004, 06:33 PM	#7
meathead95 computer illiterate Join Date: Jan 2001 Location: Des Moines, IA Posts: 6,446	what about your neutral safety switch? if you dont have it all the way in park or the switch is wearing out that could cause it not to crank over all the time __________________ 72 2wd blazer 72 swb 4x4

11-30-2004, 02:08 PM	#4
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Have you tried disconnecting the alternator to see if the draw goes away? Depending on it is wired in you can have a draw problem that can be fixed with a diode. Jim

11-30-2004, 04:02 PM	#6
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	http://67-72chevytrucks.com/vboard/s....php3?t=129594 will help you track down the short

11-30-2004, 07:28 PM	#9
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Are you doing the test with the key off? The ignition fuse should have no draw with the key off...regardless of what is hooked to it __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

11-30-2004, 07:36 PM	#10
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	That makes since. So, with that tidbit of information... He says the draw is still there with the ign switch connector pulled off. Is there something slagged either behind the fuse panel or in the connector? __________________ The truck... you hear that? No really, you did hear that?!!!

11-30-2004, 07:43 PM	#11
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	If I am reading the posted diagram right the ign fuse draws power from the ign switch. It is not bussed. Looks like power runs from the ign switch to a splice. 1 part of the splice goes to the coil other part to ign fuse wich then goes to the fuel gauge feed on the instrument connector. __________________ The truck... you hear that? No really, you did hear that?!!!

11-30-2004, 08:04 PM	#12
68speedalert Semi-Senior Member Join Date: Feb 2003 Location: Washington, MO Posts: 390	Good job chikenwing. With the key off it shouldn't matter if the ignition fuse is in or out. There shouldn't be any voltage there. Sounds like and ignition SWITCH is the problem. __________________ '68 50th Anniversery LWB Custom Fleetside, '77 305 v-8, turbo 350, factory speed alert (still works), '71 drivetrain w/front discs. Some call it ugly yellow, others call it Ochre '83 Jeep CJ-7, <80,000 miles, original owner '04 Chevy Suburban, 4x4, 2500, 6.0 ltr, Predator Diablo programmer '95 GMC K1500 Extended cab

11-30-2004, 08:30 PM	#13
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	Don't be too fast on the kudos. Could be 1 or more bugs in there. Double check this checking for coil power with key off. Would the fuel gauge and coil burn up enough to kill a battery so fast? Hope I'm helpin. __________________ The truck... you hear that? No really, you did hear that?!!!

11-30-2004, 09:27 PM	#14
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	yes, a powered coil would drain the battery, quicker than that IMO. However, he unplugged it and the amp draw remained the same, so that is not the problem. If it was the problem, his coil would have burned up by now too.

11-30-2004, 10:40 PM	#15
Don Smith Registered User Join Date: Jul 2000 Location: Hampton, Ga, USA Posts: 217	I had a intermittent sticking anti-dieseling solenoid the caused similar problems. The solenoid is usually located just below and to right of radio under the dash. __________________ 68 Short Stepside, 350, quadrajet, 700r4, 3:73 posi, power front discs, HEI, Factory Air, Tilt, Tach, accelerator cable instead of rod, sway bar. 96 Impala SS 97 Monte Carlo

11-30-2004, 11:43 PM	#16
mr402 Registered User Join Date: Jan 2004 Location: Elmira, Oregon Posts: 449	Place to start would be to see what fuses are hot with the ignition off. Should be an easy check with a voltmeter. There is also a tap or two on the fuse box that are not fused and are hot all the time. Put your amp meter back on the battery and pull just the hot fuses one at a time until you find the one that causes the current to drop. If you don't find it that way check the wires that plug directly into the fuse box and pull them one at a time. Things that come to my mind are the lighter, dome light and headlight switch. If you have a clock or stereo w/secondary wire to keep the clock/memory alive they should be checked as well. Good Luck! Finding them can be a $itch



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11-30-2004, 11:52 PM	#17
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	I like a good puzzle. On someone else's truck. Will be real interested to find out what the bug is. When I get home I'm gonna trace it out on my diagram. There has to be some more items on the circuit. If there is no other components the only thing left is the wire itself and the fuse box. __________________ The truck... you hear that? No really, you did hear that?!!!

12-01-2004, 02:25 AM	#18
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	OK. Went home and pulled out my old harness. The ign fuse IS fed from the ign switch. The ign fuse powers pin 3 of the cluster connector wich feeds the fuel gauge. There are 2 taps immediately below the ign fuse on the block. These are unfused accessory taps fed by the same ign switch wire to the ign fuse. There is a splice before the fuse that feeds the coil. With the key off, there should be no power to the ign fuse. PERIOD. If there is the switch is likely bad. The nearest terminal on the back of the block is the reverse light fuse. I doubt it is arcing over to the ign fuse. If you can pull your ign switch connector and there IS power on the ign fuse. Disconnect the battery, find the pink wire from the engine bay connector, trace it back and ensure there has been no arcing all the way to the coil. No find there, pull the fuse block in the cab and trace the 12gauge pink wire back till you see what has arced/melted over to it. The pink wire will lead from the fuse to a splice, the splice will lead to the ign switch connector and to the inside half of the bulkhead connector. Hope this helps. If you need pictures I can provide but it will be tomarrow evening before I can. Rich __________________ The truck... you hear that? No really, you did hear that?!!!

12-01-2004, 11:54 AM	#19
Don Smith Registered User Join Date: Jul 2000 Location: Hampton, Ga, USA Posts: 217	In my previous post to this thread I said anti-dieseling Solenoid, I ment to say Relay. __________________ 68 Short Stepside, 350, quadrajet, 700r4, 3:73 posi, power front discs, HEI, Factory Air, Tilt, Tach, accelerator cable instead of rod, sway bar. 96 Impala SS 97 Monte Carlo

12-02-2004, 11:27 AM	#20
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	Sorry I haven't posted since posting this question guys. Work came up and I haven't been off until this morning (24 hour shift). Thanks for all of the great posts! I will work on it this afternoon after I get a little sleep and post what I find. Chickenwing, Thank you for the in depth trace of the wiring! I will look at that this afternoon. My guess is something has to be arcing, I because I just can't figure out how the coil and the ignition switch can both be pulled, and the battery cstill pull the amps, when I know the culprit is on the ignition fuse line somewhere. I will give an update in a little while. Shawn __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

12-02-2004, 11:41 AM	#21
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	...hmmm Whatever accesories you have plugged into the 2 taps below the ign fuse would be able to draw the power. __________________ The truck... you hear that? No really, you did hear that?!!!

12-03-2004, 04:22 PM	#22
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	O.K. I found the problem, but I don't know exactly what to do about it. I unplugged and checked wires all over the truck, then I came to the gauge cluster. I unplugged it and the draw went away. Great!! I found it!!! Then I tried to narrow it down. I undid the posts for the temp gauge and the draw went from 2.6 to 1.8. Next I undid the post for the fuel gauge and the draw went down to .01. Perfect!!! but now how do I fix the problem? Both gauges work perfectly. Is it possible that both of the resistor things on the back went bad at the same time? Could they create the problem? Any help would be appreciated! Shawn __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

12-03-2004, 04:30 PM	#23
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	Now was that with the key off or on? __________________ The truck... you hear that? No really, you did hear that?!!!

12-03-2004, 04:34 PM	#24
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	key was off. __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

12-03-2004, 04:59 PM	#25
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	The way I see it you need to figure out where the power is coming from. That circuit should have no power with the key off. Those 2 items are supposed to draw power. 1.8 ohms or amps would be in range for a gas gauge, means you are sittin on E baby. 0-90 ohm sweep on the fuel sender. Dunno on the temp. But sounds reasonable. You need to figure out where the power is bleeding over from. I know I am asking qestions over again. But I am not there. You sure the power is still there with ignition switch connector pulled off the switch? If it is and it it is not there when you pull the cluster connector, maybe something is bleeding over from the printed circuit board. Take a voltmeter to each pin on the instrument connector and find out wich pin has the voltage on it. __________________ The truck... you hear that? No really, you did hear that?!!!

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