LUVTruck.com

Hello all. I've got a 73 luv that won't charge. I've replaced the alternator and regulator (and battery, for good measure). Cleaned/changed as many contacts/grounds/etc as I can find. Fusible links are good.

This has been ongoing for some time and I have basically been charging the battery manually and only running during the day (headlights kill the battery too quickly). With the new alt and regulator I figured it would be solved, or I would at least be able to narrow it down from there, but I've been stumped on what could be the issue. Then a friend mentioned that there may be a wire that runs through the ignition switch that "engages" the regulator when the key is turned, which then allows the alternator to do it's thing. Is this true?

From reading nearly everything I can find on the forums, I know that the Luv's ignition switch is not the most reliable, so this seems like a plausible explanation for the lack of charge. My wife's dad (who we got the Luv from) said when it stopped charging, the dash seemed to stop working about the same time, which also seems plausible if one of the wires from the switch was not making contact properly.

I've been trying to use the wiring diagram to trace what should be going where. Looking at the bottom connector for the regulator (on the diagram), the top middle wire (0 85W ?) looks like it goes to the fuse box, I am having trouble following it from there (the diagram is a little fuzzy, and lets face it, not that "clear" to begin with, IMHO). Anyone know what this is for? Am I on to something? Also, what does "0 85W" mean (or any of the other labels for the wires)? I'm guessing it means "white"? What do the other numbers, etc mean?

The answers to those questions would be helpful, but what would be REALLY helpful is if someone could take a volt meter and simply probe the connector that is at the regulator and tell me what voltages should be present on each pin when the engine is running and the alternator charging. From there I could determine what was "missing", and working backwards in this case I think I could determine what was faulty.

My wife wants to go camping with the Luv for our first anniversary, which is this weekend (got it just before we got married). I know, I know...how sweet...
I'd like to try to make it happen (I got the brakes fixed, just need it to charge!). All help is greatly appreciated.

Sorry this is so long... I tend to ramble...

0.85W is a white wire with an 0.85 mm conductor.

With the engine running, but not charging, check the voltage at the bat and ign terminals at the regulator. if you done have 12-14 volts, check the fuse box. Numerous threads discussing the bad connections there.

Yes, even the schematic in the shop manual sucks, sucks, sucks. The reduced version in my Chiltons is even worse.

Thanks for the info!


That's exactly what I would like to do, but I don't know which terminal(s) at the regulator is/are for the ignition terminals. Is it the 0.85W that goes to the fuse box? What about the other wires? Can anyone read the schematic and detail what each is for and possibly what voltage should be present in different situations(running, off, etc)?

From the above reply it sounds like there is a wire that goes through the ignition switch, so my theory could be plausible?

Thanks again!

I have a 6 wire plug coming off the VR. White/ red and white to inside, white to the alternator on top. White/green, white/green, and black to the alternator on the bottom.

Key off, Nothing except 12 V on the big black wire to the alternator. Engine running, 13, 13, 6, 13, 4, and the small black wire is grounded.

The key has 4 wires, black from the battery, blue to a terminal on the fuse holder riveted to one end of the fuse holder for the accessories, black/yellow to a terminal on the fuse box, and black/white to the starter. Just because the wire into the fuse box is hot and a good fuse doesn't mean the wire from the fuse box is hot.

Thanks Labman,
I am going to copy your ignition wire information and hang it on the garage wall!

Here's another suggestion, I have a friend with his own A/C repair show and he has Mitchell Wiring Schemetic Books for all cars and trucks, both foreign and domestic. I have borrowed one of these books, taken it to a copy center, copied the desired wiring diagram and then had it enlarged (blown up) to a workable easily read diagram. One time I had three 3' X 5' sheets taped together. They covered the roof of the car I was working on!
Of course you will probably have to do the copying of the original yourself, because the copy center clerk will balk at possible copyright infringement, but this is easy to do.
The total cost was less than 20 bucks, but is invalueable when tracing wires. I have used colored pencils to trace out circuits on my copies.
If this is not possible send me a message and I can do this for you too.
Personally, I recommend you switch over to a one wire Delco alternator, then your charging problems are all gone! Unless you wish to keep your Luv all original?
You can find lots of leads on doing this under the "Drivetrain Mods" section, simply scroll down to "One wire Alternator" question. They also have pictures of how to modify your stock alt mounts.
Good luck, Congratulations on your anniversary!!
scjconv-dusty