GP Controller Card Bypass - What went wrong?

[Buckmaw]

Had some time yesterday afternoon and installed a momentary switch and a light. I cut the wire going to the GP Controller Card and ran that to the switch.
You can see what I did in the sch.

This morning it was about 27F out. I turned the key on like normal. Pressed the button, the blue light come on, held it for 10 seconds, released the switch and hit the starter switch...

The motor would turn over but would not start. I tried this 3 times before splicing the light blue wire back into the controller card. After that, the truck started right up.

Where did I mess up?

 

[Dieselsmoke]

If the truck started up using the controller card, why are you bypassing it?

 

[Buckmaw]

If the truck started up using the controller card, why are you bypassing it?

Because the card in afterglow mode, sometimes make the relay "chatter". I was going to bypass the card and be done with it.

 

[Blood_of_Tyrants]

Your LED might not be letting enough current go through to energize the relay. Try without the LED.

 

[gaunt1969]

your chattering relay most likely is not your card. With your card in and truck running and when the relay is chattering measure the voltage at the pos and neg of the front batt and then on the back batt. If one or both are less than 14 volts that's why you relay is chattering. One alt could be charging less than it should but enough to keep the batts up enough not to give you starting problems. BTW the idiot lights for the alts. are idiots. they dont tell you that the alts are charging low.
My 1028 did the same thing and volt meter was in the green. lower section of the green. but green al the same.

 

[mistaken1]

You need a direct path to ground from the switch. Then put the LED in parallel with that path. (run another #12 or #14 from the ground side of the switch to ground and leave the LED as is)

The LED limits the current through the coil so that the LED glows however that is not enough current to allow the coil to build enough flux to pull in the contacts.

 

[Buckmaw]

You need a direct path to ground from the switch. Then put the LED in parallel with that path. (run another #12 or #14 from the ground side of the switch to ground and leave the LED as is)

The LED limits the current through the coil so that the LED glows however that is not enough current to allow the coil to build enough flux to pull in the contacts.

Yea... that is the conclusion I come to also...

I will fix it when I get done with the spare tire mount on my 101a2.

 

[Sgt Hulka]

I had some fits with a couple of flakey controller cards, but once I got a good one, I LOVE IT... Search the threads for chattering relays. Blood of Tyrants has a neat trick using a diode on the gp relay to ease chattering...

 

[Buckmaw]

your chattering relay most likely is not your card. With your card in and truck running and when the relay is chattering measure the voltage at the pos and neg of the front batt and then on the back batt. If one or both are less than 14 volts that's why you relay is chattering. One alt could be charging less than it should but enough to keep the batts up enough not to give you starting problems. BTW the idiot lights for the alts. are idiots. they dont tell you that the alts are charging low.
My 1028 did the same thing and volt meter was in the green. lower section of the green. but green al the same.

gaunt1969 wins this thread...

It turns out my #1 alternators output was below par. I did notice that my volt meter was not running in the middle green, but lower green and I was not having any lighting or starting issues.

I started it up and then took a hammer to the #1 alt and "whammo", it started charging at 14vdc. So off to the parts house to get a replacement alternator as this one was only 4 months old and has a lifetime warranty.

Changed it in the parking lot and all is good in the world. My controller card and relay are acting normal now. The good thing is I have the wiring and switch already installed in case the card ever kicks the bucket.

Thanks again for the suggestion. It's always good to get outside opinions on a gripe.

I owe you a beer.

 

[goldneagle]

gaunt1969 wins this thread...

It turns out my #1 alternators output was below par. I did notice that my volt meter was not running in the middle green, but lower green and I was not having any lighting or starting issues.

I started it up and then took a hammer to the #1 alt and "whammo", it started charging at 14vdc. So off to the parts house to get a replacement alternator as this one was only 4 months old and has a lifetime warranty.

Changed it in the parking lot and all is good in the world. My controller card and relay are acting normal now. The good thing is I have the wiring and switch already installed in case the card ever kicks the bucket.

Thanks again for the suggestion. It's always good to get outside opinions on a gripe.

I owe you a beer.

I think its worth a 6 pack!

 

[gaunt1969]

dont dump the alt they are easy to repair, you likely just have a corosion problem . take it apart and look

 

[Buckmaw]

dont dump the alt they are easy to repair, you likely just have a corosion problem . take it apart and look

This was not a .MIL Alternator.

It was a Remy from OReilly: Pt # 01-0136
1975 Caddy Commercial Chassis
100 amp

Exact copy of the .mil alt except for the isolated ground.
$95 with a $15 core
Lifetime warranty.

It cost me nothing to change out the faulty alternator and I have a extral .mil
alt for a backup.

 

[grayw0lf]

When you speak of GP relay chatter, is it only while the GP's are heating as they should? Or is it still chattering when you're 30 miles down the road, like mine does???

 

[Jonas]

Why hook up an extra bulb to show glowing in progress when you have one in the dash?
splice n dice into that one instead!