Fun with Relays

[pidgeon]

A few weeks back, my power steering belt broke (ahhh yes... nothing is more fun than steering and breaking a very heavy, exceptionally quick brick without power steering...) I drove it home and replaced all of the belts. Yes, I know... this shouldn't have anything to do with starter relays, but bear with me here..

Immediately after getting the truck (which has been thusly dubbed "Soilent Green" by the neighbors) back on the road, I notice my voltmeter is staying in the yellow. Hrmmm. I make a mental note to check on it and somehow forget. Which brings me to this morning.....

I go to start her up. Glowplug light on. Gen2 light on... no gen1.... weird. I turn the key. Click click click from the relay cluster under the dash. I use the other car, stop at napa on the way home (because, hey, Gen1 light is burnt... might be the issue..) and swap the bulb. Click Click Click....

Out comes the voltmeter. 30.1 across both batteries. I go and try it again. I turn the key and leave it on glow plug. Gen1 and Gen2 come on. I get out and look under the hood real quick and hear a different *click*click*, this time at the relay right on the firewall on the drivers side behind the aircleaner. 3 clicks and stop.

So, now, as I dive into the TM wiring diagrams to figure out what the **** is going on, so I can fix it (and since I'm there install the doghead relay mod, since I'm paranoid as all get out about frying expensive to fix things), I humbly ask the MV gods and goddesses "WTF?"

In other words.... any ideas on where I should start? I've searched the forums and have a few clues (voltmeter relay is my main suspect), but, I'm always open for expertise.

-beth

PS. back to the power steering belt... I checked all my connections on the alts... they seem fine. I checked to see if the flailing belt took out anything.... if it did, i'm not seeing it. 30v across makes me think that all is fine from the alt side of things and that is is a relay thing either caused by a spike from my belts, lots of wet PNW weather or old age....

 

[HAWKMAN]

Beth.....just a thought, maybe check/clean your grounds....these trucks are kind'a finicky about their grounds.

 

[Warthog]

Where you able to start the truck? Or did you just get the "clicks"?

When you are turning the key, is it in the start postion or just run position?

30v on the batteries is a little high. It should be 28v~29v max with the engine running, 24v~25v with the engine off.

First thing is to disconnect the batteries and check voltage for each one. ~12.5 with a full charge. Clean the posts and cables while you are at it.

The relay on the fireway is the Glowpug Relay. Working properly you should hear one click when it turns on or off. Chattering indicates a problem in the system.

Your first "click" issue sounds like the starter relay, might be going bad.

The voltmeter relay next to it seems to be funtional because the volt meter is moving.

The other relay is the Gen2 relay and it is working because the Gen2 light wouldn't come on unless it was working.

Check the batteries and let us know the status. You might want to have them load tested at the parts store.

Then move on to the alternators. One on them may be bad (guessing Gen1)

 

[pidgeon]

>Where you able to start the truck? Or did you just get the "clicks"?

Just clicks.

>When you are turning the key, is it in the start postion or just run position?

Start. When I turn to start, Gen2 comes on. Gen 1 comes on a moment later (although come to think of it a tad less bright, even with the new bulb).

>The relay on the fireway is the Glowpug Relay. Working properly you should hear one click >when it turns on or off. Chattering indicates a problem in the system.
>Your first "click" issue sounds like the starter relay, might be going bad.

Replacing once my lawnmower relay gets here.

>Check the batteries and let us know the status. You might want to have them load tested at the >parts store.

One is from 2006. The other 2009. I'll yank them this weekend along with the alternators and get them tested.

 

[Warthog]

Just a guess here but the 2006 battery may be bad. I have seen them last longer but three years is usually the max.

The parts stores can test the alternators. Just tell them to connect the ground clamp to the ground post and not the case.

Good luck.

 

[pidgeon]

Yeah, I'm eyeing the battery too. **** troublemaker. So, list for tonight is:

- Undo alt wires, clean up, dielectric grease and retighten.
- Undo battery wires, clean up, dielectric grease and retighten.
- Undo ground and clean it up
and then... while I'm at it I'm just going to replace the gen2 relay, volt relay, starter relay and the GPR. Yes, it's a shotgun approach but I see it as "preventative" (aka debugging electrical systems is not my strong point)

Anyone have the parts number for the gen2 and volt relays. My parts monkey guy isn't too swift and I want to stop on the way home.

 

[Warthog]

Anyone have the parts number for the gen2 and volt relays. My parts monkey guy isn't too swift and I want to stop on the way home.

The -34P parts manual shows a GM part number for both relays is

12033862

Cross references to NAPA as

MPE AR272SB - $8.49 Milage Plus Electric
ECH AR272 - $11.49 Eclin Ignition

 

[Crash_AF]

Anyone have the parts number for the gen2 and volt relays. My parts monkey guy isn't too swift and I want to stop on the way home.

Ask for two A/C relays for a 1990 Jeep Cherokee. They're just standard Bosch relays. They might have a mounting tab that the original doesn't but you can just break it off with a pair of pliers.

Later,
Joe

 

[pidgeon]

Ok, so...

Both Gen2 and VM replaced. Doghead mod done. GPR done. batteries: Front (2006) reads 14.5. Rear (2009) reads 20. Cleaned obvious connections to ground (I'm sure I missed some, but it started raining and is getting dark), cleaned DS alt connections, cleaned battery connections.

Turn key to start. Good lights on Gen1 and Gen2 (Gen1 is significantly brighter than before. Equal to Gen2 now.). Glow plugs do their clunk clunk sound. I crank her and the starter relay goes CLICK CLICK CLICK.... and no start.

Battery and more ground cleaning tomorrow. If that doesn't work... alt?

 

[swyne]

Could there be a chance the starter is shot? Or perhaps the cable going to the starter (hot wire) could be loose or cruddy! Try rapping the starter, it could be stuck! Just my 2 cents. Your voltage is way to high on the one bat 20V. The other is perfect 14.5V. The extra voltage could be frying something like a relay. Or a wire. Please keep us informed!!

 

[Crash_AF]

The rear reads 20 across its own two posts or across both batts? If it's 20 across itself, that battery is severely overcharged. If it's 20 across both batts, it's severely undercharged. From terminal to terminal on the rear battery it should read between 12 and 14V and across both batteries it should read between 24 and 28V

If it's 20 overall I can believe that it's only going clunk. Charge the rear battery and see if that helps, or put jumper cables from your other car across ONLY the rear battery's two terminals and try to start. Do NOT let the cables touch any other source of ground on the CUCV or you will fry the other vehicle's electrics.

Later,
Joe

 

[pidgeon]

It's reading 20 on the rear, post to post.

 

[amphi]

Sounds like the wire connecting the two batteries together has a bad connection.

Check the voltage from the + on the front battery to the – on the rear. If the connection is good it will read near zero. If bad it will read something near 12v.

Good luck!

 

[pidgeon]

Didn't get to do anything tonight but an interesting side note (which is making me lead more and more to batteries/cables)....

I was cleaning the inside of the truck (tools strewn about == blech) and accidentally tapped the top two posts on the starter relay. Heeeeyyyyy... I know that sound. I grabbed my big screwdriver and sure enough I heard the distinct sound of dying battery turning a starter (rooorrr... roor... rrrr. Like my impression?)

 

[Crash_AF]

Remove all the cables from the rear battery and see what it reads post to post... I highly doubt that it is truly at 20V. Just out of curiosity, is your multimeter an automatic ranging one? It might be reading something other than volts (like Milivolts or something).

At 20V across the rear battery alone there is definitely a problem. I would replace that battery with a new/known good one (if it's only 1 year old it should still be under warranty) and see if that solves your problem.

Later,
Joe

 

[southdave]

mine was doing that very same thing found a cathoid diaode thingy broken in half Warthog gave me the part Number I recharge the battery and installed the electronic thngy and runs starts ect..

 

[Ken_86gt]

You may have fixed the charging problem with the work you have done, but the 20v on the rear battery is a problem. I suggest charging the rear batter for a while and see if it works.

 

[Warthog]

mine was doing that very same thing found a cathoid diaode thingy broken in half Warthog gave me the part Number I recharge the battery and installed the electronic thngy and runs starts ect..

The Diode Dave is talking about is located in the puple wire at the back of the engine. All of them I have seen have been wrapped in gray Duct Tape.

The diode is part of the "water-in-fuel" circuit.

http://www.steelsoldiers.com/cucv/49392-purple-wire.html

 

[pidgeon]

Ok, well, replaced all my terminals since after cleaning one I couldn't get it to tighten back down. Dielectric grease and liquid taped (they have it in green!) everything I should. Now it's just waiting for a friend to pop over with his deuce to jump the cucv. I should have a few of those diodes in my lab, I'll have to check.

Funny thing though. I was working on something unrelated last night (nixie tube clock) and had my volt meter out to tune the variable resistor and it would not get a reading worth a hill of beans. It would read for a moment and then drift around and then bump to -1 error code..... which leads me to suspect the the piece of garbage is in fact, a piece of garbage and was giving me incorrect readings.... time for a new one.

 

[Ken_86gt]

You know that you can jump with standard 12v car, one battery at a time. In your case just jump the back battery since it had low voltage.