Volt meter readings
Cargo Master
Joined: Mar 2007
Posts: 2,856
Likes: 1,037
Electricity likes a nice path to get to where it's going. All those butt connectors got to go. Do a voltage drop test. Google it if you do not know. The perfect test for your problems, assuming you want to find the cause.
Alternators are not designed to give full charge at idle. If they did, they would explode at redline. I do not know your rating, but if you got a 90A alternator, I think at best, it might charge half that at idle. If you got all your electrical consumers on, it would not surprise me that the system is actually discharging. That is why, whenever I am in rush hour traffic [in my area, you could go 5 miles in an hour] I start to turn off the consumers that suck the most juice.
Alternators are not designed to give full charge at idle. If they did, they would explode at redline. I do not know your rating, but if you got a 90A alternator, I think at best, it might charge half that at idle. If you got all your electrical consumers on, it would not surprise me that the system is actually discharging. That is why, whenever I am in rush hour traffic [in my area, you could go 5 miles in an hour] I start to turn off the consumers that suck the most juice.
Thread Starter
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Cross-Country
Joined: Dec 2024
Posts: 76
Likes: 12
Electricity likes a nice path to get to where it's going. All those butt connectors got to go. Do a voltage drop test. Google it if you do not know. The perfect test for your problems, assuming you want to find the cause.
Alternators are not designed to give full charge at idle. If they did, they would explode at redline. I do not know your rating, but if you got a 90A alternator, I think at best, it might charge half that at idle. If you got all your electrical consumers on, it would not surprise me that the system is actually discharging. That is why, whenever I am in rush hour traffic [in my area, you could go 5 miles in an hour] I start to turn off the consumers that suck the most juice.
Alternators are not designed to give full charge at idle. If they did, they would explode at redline. I do not know your rating, but if you got a 90A alternator, I think at best, it might charge half that at idle. If you got all your electrical consumers on, it would not surprise me that the system is actually discharging. That is why, whenever I am in rush hour traffic [in my area, you could go 5 miles in an hour] I start to turn off the consumers that suck the most juice.
Cargo Master
Joined: Mar 2007
Posts: 2,856
Likes: 1,037
With a voltage drop test that would take you just a few seconds in your life, instead of thinking it's ok, you will know it is ok. When I was a Shop Foreman, I would get mad at my techs when they said something like that. I would tell them, I don't pay you to think, I pay you to know. I get if the test would take hours, but the test is too easy and when it comes to diagnosis, facts will dictate the path to follow. The more you think, the more likely you will take the wrong path.
Just saying.
I tend to think that the battery is only there to start the engine. Once the engine is running, the alternator provides ALL the power to the electrical consumers. The battery is just sitting there doing nothing, but to start the engine when you shut it off again.
Yes, the battery does provide power to the system when the alternator can't, such as full wipers, full heat, A/C, lights, etc sitting in traffic wondering why it's not moving. At some point of time, the battery might drain down to nothing. Engineers never designed the system to be run that way for that long.
Just saying.
I tend to think that the battery is only there to start the engine. Once the engine is running, the alternator provides ALL the power to the electrical consumers. The battery is just sitting there doing nothing, but to start the engine when you shut it off again.
Yes, the battery does provide power to the system when the alternator can't, such as full wipers, full heat, A/C, lights, etc sitting in traffic wondering why it's not moving. At some point of time, the battery might drain down to nothing. Engineers never designed the system to be run that way for that long.
i ain't rite
Joined: Mar 2005
Posts: 65,586
Likes: 5,615
From: Marlboro Mental Hospital.
the volt gauges in these trucks were marginal even when new.
on my 88 it does not even work unless i smack the top of the dash. a lot of trucks went out with needles bent too close to the gauge face and they stick when no voltage is supplied to the.
check woltage at battery with engine running.
and for heater motor only having high setting, there is a blower motor resister that tends to burn out over time.
here is one on amazon for $16.99 :
on my 88 it does not even work unless i smack the top of the dash. a lot of trucks went out with needles bent too close to the gauge face and they stick when no voltage is supplied to the.
check woltage at battery with engine running.
and for heater motor only having high setting, there is a blower motor resister that tends to burn out over time.
here is one on amazon for $16.99 :
Thread Starter
|
Cross-Country
Joined: Dec 2024
Posts: 76
Likes: 12
With a voltage drop test that would take you just a few seconds in your life, instead of thinking it's ok, you will know it is ok. When I was a Shop Foreman, I would get mad at my techs when they said something like that. I would tell them, I don't pay you to think, I pay you to know. I get if the test would take hours, but the test is too easy and when it comes to diagnosis, facts will dictate the path to follow. The more you think, the more likely you will take the wrong path.
Just saying.
I tend to think that the battery is only there to start the engine. Once the engine is running, the alternator provides ALL the power to the electrical consumers. The battery is just sitting there doing nothing, but to start the engine when you shut it off again.
Yes, the battery does provide power to the system when the alternator can't, such as full wipers, full heat, A/C, lights, etc sitting in traffic wondering why it's not moving. At some point of time, the battery might drain down to nothing. Engineers never designed the system to be run that way for that long.
Just saying.
I tend to think that the battery is only there to start the engine. Once the engine is running, the alternator provides ALL the power to the electrical consumers. The battery is just sitting there doing nothing, but to start the engine when you shut it off again.
Yes, the battery does provide power to the system when the alternator can't, such as full wipers, full heat, A/C, lights, etc sitting in traffic wondering why it's not moving. At some point of time, the battery might drain down to nothing. Engineers never designed the system to be run that way for that long.
Thread Starter
|
Cross-Country
Joined: Dec 2024
Posts: 76
Likes: 12
the volt gauges in these trucks were marginal even when new.
on my 88 it does not even work unless i smack the top of the dash. a lot of trucks went out with needles bent too close to the gauge face and they stick when no voltage is supplied to the.
check woltage at battery with engine running.
and for heater motor only having high setting, there is a blower motor resister that tends to burn out over time.
here is one on amazon for $16.99 :
https://www.amazon.com/Blower-Resist...35177138&psc=1
on my 88 it does not even work unless i smack the top of the dash. a lot of trucks went out with needles bent too close to the gauge face and they stick when no voltage is supplied to the.
check woltage at battery with engine running.
and for heater motor only having high setting, there is a blower motor resister that tends to burn out over time.
here is one on amazon for $16.99 :
https://www.amazon.com/Blower-Resist...35177138&psc=1
Thread Starter
|
Cross-Country
Joined: Dec 2024
Posts: 76
Likes: 12
That would make sense on why I only have the high fan speed setting. Nothing else works there
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Brett Foote
FTE Legend
Joined: Nov 2015
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From: Angier, NC
the volt gauges in these trucks were marginal even when new.
on my 88 it does not even work unless i smack the top of the dash. a lot of trucks went out with needles bent too close to the gauge face and they stick when no voltage is supplied to the.
check woltage at battery with engine running.
and for heater motor only having high setting, there is a blower motor resister that tends to burn out over time.
here is one on amazon for $16.99 :
https://www.amazon.com/Blower-Resist...35177138&psc=1
on my 88 it does not even work unless i smack the top of the dash. a lot of trucks went out with needles bent too close to the gauge face and they stick when no voltage is supplied to the.
check woltage at battery with engine running.
and for heater motor only having high setting, there is a blower motor resister that tends to burn out over time.
here is one on amazon for $16.99 :
https://www.amazon.com/Blower-Resist...35177138&psc=1
Check the ALT output at the battery. Nothing on you should have 13.5 to 14.5 volts at idle you can bring the RPM up a little if you want but it should be 13.5 - 14.5 volts.
Not turn on everything head lights high, blower on high and anything else that pulls power. Bring the RPM up to 2500 and check the voltage at thew battery you should get the same 13.5 - 14.5 volts and if not the ALT / REG is bad and only reason why you have not ended up with a dead battery is you bring it inside and charge it between use.
You are pulling power out and not putting anything back in if battery is at 12 to 13 volts as that is what the battery reading is when you pull it off the charger.
As for the ALT being new, New dose not mean good only testing and it putting out 13.5 to 14.5 volts shows its good.
The regulator is built into the ALT and I dont know how you test that ALT to bypass it to do a full field test to see if the regulator is bad or the ALT.
But to me that ALY is in question of being good.
Dave ----
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Cross-Country
Joined: Dec 2024
Posts: 76
Likes: 12
Did a volt drop test and it was most certainly the Alternator even though oriellys tested it and said the alternator was good... it was in fact not. Hooked it up, hooked the wires and we are back to normal on the gauges. Thanks all for your input 👍
Lead Driver
Joined: Jun 2021
Posts: 5,221
Likes: 805
Add a ground while youre in there
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Cross-Country
Joined: Dec 2024
Posts: 76
Likes: 12
I will for sure. First thing in the morning I'll tidy it up and do that. I got it in and running and tested it before it got dark af and cold. Finishing touches in the morning before I got chop more trees! Thanks again!
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