Limit of GM Switched ignition for relays?

[wew lad 5,000+ posts]

Anyone know what the limit of the GM switched ignition relay is? Also curious to know what a simple 5 amp relay draws on the switching terminal coil and if its within the limitations of a switched source

I need to tap into it, or another switched 12v source to run in line with a resistor and bulb for an alternator that's not getting the appropriate voltage from the dash L field wire due to it being in parallel with another alternator.

If anyone has knowledge of how the electronic dash light works on 99-06 gm full size's I'd really appreciate it. My belief is that the PCM controls it but is limited in its ability to put out enough magnetic field to keep two large case alternators excited vs the oem single stock small case. On occasion the voltage going into the L terminals is nearly 0 causing one or both alternators to shut off until I rev past 5k or buddha blesses me (i.e. idfk)

here's the most accurate schematic so far:

and this one is from a 03-07classic with the newer pcm controls for voltage sensing. easier to read, just ignore the C terminal field generator duty cycle

Click to read more...

 

[adulbrich 5,000+ posts]

Just run an external relay for your alternators. Wire it into something else that is always turned on when your truck is running.

Problem solved.

 

[Stellar1024]

yeah... I think you're making it more difficult by worrying about the factory limits opposed to just creating an aftermarket circuit...

 

[wew lad 5,000+ posts]

Just run an external relay for your alternators. Wire it into something else that is always turned on when your truck is running.
Problem solved.

that's what I'm asking? what should I tap into that will be able to output enough current to turn on a relay that will in turn be run from the battery to the L field with a resistor in line

 

[adulbrich 5,000+ posts]

that's what I'm asking? what should I tap into that will be able to output enough current to turn on a relay that will in turn be run from the battery to the L field with a resistor in line

Aren't daytime running lights on all the time when the vehicle is running?

I switched mine to LED's because i thought they look cool. LED's draw wayyyy less current than incandescent bulbs. My LED turn signals blink twice as fast because they draw so much less current. I couldn't even use LED turn signals on my motorcycle because they didn't draw enough current. The switch/relay would just buzz until I added resistors.

If you got some LED daytime running lights on ebay for $10, you could tap into that circuit and be golden //content.invisioncic.com/y282845/emoticons/thumbsupwink.gif.129404938effda6ad9cca39e7f4b58a3.gif

 

[wew lad 5,000+ posts]

Aren't daytime running lights on all the time when the vehicle is running?
I switched mine to LED's because i thought they look cool. LED's draw wayyyy less current than incandescent bulbs. My LED turn signals blink twice as fast because they draw so much less current. I couldn't even use LED turn signals on my motorcycle because they didn't draw enough current. The switch/relay would just buzz until I added resistors.

If you got some LED daytime running lights on ebay for $10, you could tap into that circuit and be golden //content.invisioncic.com/y282845/emoticons/thumbsupwink.gif.129404938effda6ad9cca39e7f4b58a3.gif

yeah my DRL's are actually unplugged, so that might be a good source. except they turn off at night. so no, not a good source. i dont think your DRL's are on when your night headlights are on... are they? idr mine doing that

ill probably splice in just about anything because i guarantee you thats what some of these fools do, but i might not need to because during diagnosis with resistors and lights in line with the L excitation wire I cannot no matter what get the alternator to excite. thinking i have an internal short.

just a heads up for those confused, I want a switched power source ONLY to excite the relay, NOT to run anything. The relay IS the aftermarket circuit you're referring to, but it has to be excited somehow unless i run a switch (yeah no)

 

[adulbrich 5,000+ posts]

yeah my DRL's are actually unplugged, so that might be a good source. except they turn off at night. so no, not a good source. i dont think your DRL's are on when your night headlights are on... are they? idr mine doing that
ill probably splice in just about anything because i guarantee you thats what some of these fools do, but i might not need to because during diagnosis with resistors and lights in line with the L excitation wire I cannot no matter what get the alternator to excite. thinking i have an internal short.

just a heads up for those confused, I want a switched power source ONLY to excite the relay, NOT to run anything. The relay IS the aftermarket circuit you're referring to, but it has to be excited somehow unless i run a switch (yeah no)

That sucks. Maybe tap into the wire that turns your radio on?

Alternator trouble? Maybe you should buy one of mine //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[wew lad 5,000+ posts]

That sucks. Maybe tap into the wire that turns your radio on?
Alternator trouble? Maybe you should buy one of mine //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

if i had money left over from buying/selling sure but i have a bunch of oldschool **** just sitting around lol i forwarded your post to a guy asking about HO alts on gmfs.com

honestly im pretty pissed and ill probably just go buy another ad244 from the junkyard for $50. stupid how its more expensive to replace the VR and BR. this is an alt i bought new too, not a junkyard 10+ yr old one (which apparently are better)

 

[adulbrich 5,000+ posts]

if i had money left over from buying/selling sure but i have a bunch of oldschool **** just sitting around lol i forwarded your post to a guy asking about HO alts on gmfs.com
honestly im pretty pissed and ill probably just go buy another ad244 from the junkyard for $50. stupid how its more expensive to replace the VR and BR. this is an alt i bought new too, not a junkyard 10+ yr old one (which apparently are better)

Alright, just thought I'd offer

 

[CSCStang]

I ran my 2nd alt to the ign fuse (with an addafuse) with a 20amp relay inline. 99 Silverado. 2 large case...a 320 and a 250 DC. Running great at 14.8

Sent from my SM-N920V using Tapatalk

 

[wew lad 5,000+ posts]

I ran my 2nd alt to the ign fuse (with an addafuse) with a 20amp relay inline. 99 Silverado. 2 large case...a 320 and a 250 DC. Running great at 14.8
Sent from my SM-N920V using Tapatalk

any resistor or light inline? im pretty sure they dont like 14-15v it'll fry the VR?

I really wish we had some actual electrical circuit experts on here

 

[CSCStang]

any resistor or light inline? im pretty sure they dont like 14-15v it'll fry the VR?
I really wish we had some actual electrical circuit experts on here

None that I know of. Bought the harness with the 250 from DC and plugged it all in. Might be one within the harness? No issues.

Sent from my SM-N920V using Tapatalk

 

[adulbrich 5,000+ posts]

any resistor or light inline? im pretty sure they dont like 14-15v it'll fry the VR?
I really wish we had some actual electrical circuit experts on here

Actually now that you mention resistors, when I got my quad alternators set up, I had resistors put in one of the two wires going to each alt. The guys at the alternator shop who changed my regulators insisted on putting the resistors in.

 

[wew lad 5,000+ posts]

Actually now that you mention resistors, when I got my quad alternators set up, I had resistors put in one of the two wires going to each alt. The guys at the alternator shop who changed my regulators insisted on putting the resistors in.

yeah usually between 50-100 ohms

someone told me something about the inductive load of the light being necessary but i have my doubts. when i put a resistor in line i still only had 1.3vdc on the brown wire and the resistor was too hot to touch and started smoking (which is why i think its an internal short)

None that I know of. Bought the harness with the 250 from DC and plugged it all in. Might be one within the harness? No issues.
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ill try calling them and seeing whats up

 

[wew lad 5,000+ posts]

just talked to Anthony at DC, really great guy. definitely buying my alternators from them in the future because they have such a smart team who knows what theyre doing.

he told me a 500ohm 1/2 watt resistor is what theyre using, which makes sense, because the 50-100 i was using was letting wayyyy too much current through.

you do have a resistor in line on your yellow wire @CSCStang he said if it blows or fails you wont get a light but the alternator will not output (just a heads up hopefully it helps in the future)