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The '78 seems to pop the Voltage regulator fuse after any sort of prolonged driving at speeds over 60. I lost the VR fuse this morning, but also the wipers and the heater fan. I've just checked the Series 5 PDF wiring diagrams from another electrical topic, but I'm not seeing anything immediately pop out at me. The blower for the heater is brand new. I'm guessing a ground opened up somewhere, as the fuses for the wipers and heater are fine. Any ideas?

Sorry to bug you guys with this, my wife has become really ill and I just don't have time to troubleshoot while trying to monitor three children.

Some quick checks would be much appreciated.

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

I'll take a stab at it. Use a voltmeter or test light, check for voltage to ground at both fuses. If none, then the ignition switch would be next in line as it gets the voltage from the accessory terminal there.

I have an aftermarket 3 pole marine style switch for the ignition. All of the leads for Accecories, etc. are tied to one output. I'll look at this, as I just replaced the ignition switch. Thanks

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

I got a key made for the factory ignition switch I have here.

Can I get someone to help me out with connections? Either a photo of the truck side wiring harness or drawing of the 5 prong connector and the colors in each location?

I have the manual, but the switch is not labeled 1-5, so the color locations on each lead are a bit of a mystery. What color is 'L' anyway?

Thanks!!

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

I do know that the L is for blue. Because B is for black.

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OK, I'm over it. Where's the beer?

After messing with it for a bit, I found that the 'L' is indeed blue, thanks.

Turns out the ignition switch I have is no good. It only provides contacts in two of the three expected states. So, I put the 3 prong switch back in. I currently have it wired like this:

Both BY's and L to IGN
B to BAT
BW to SOL

It's been running like this since I've owned it, so I'll probably have to take a look at the fuse box and the hardwired fuel pump. The fuel pump is directly wired to one of the BY leads in the cab. It might even be wired directly the coil, if memory serves me. I know it's hacked, but outside of the fuel pump the wiring is suprisingly untouched. It would be nice to at least have the fan and wipers operational again.

I found a 4 prong switch for marine applications that might work, I'm not sure the BY and the L should be perpetually on the same contact. Looks like it's set up this way due to the fuel pump wiring.

I found a bunch of old relay's from an alarm system someone had put in an S-10 I had. I think someone posted a how-to on using an aftermarket relay somewhere, so I'll go find the fuel pump relay thread here and see if I can set that up properly. The wiring in these trucks is so simple, there can't be too many circuits to chase down. I did mention I used to work on Saab 900's, right? hahaha...40+ fuses in that box, plus 6-10 relays, plus the ECU, plus the underdash relays...

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

It wipes. It blows.

I started isolating circuits, and found that everything led to the voltage regulator. I took the VR cover off and it was downright beautiful in there, all that copper and windings and such. Clean as a whistle, and contacts looked great. I then pulled the harness connector apart and a handful of dirt fell out. Hmmmm.

Cleaned it out with some contact cleaner, hit it with the battery brush, slapped a little silicone on the prongs and the wipers and fan started working. Still need to figure out the fuel pump wiring, but at least now maybe I can go to the dump before (if?) I sell it...

After further investigation, it looks like the BY and L can be on the same terminal without any significant issues. The ON position feeds the BY power through to the L, so hardwiring it simply eliminates one switch position. Someone please correct me if I'm wrong on this.

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

I am thinking I might have the same problem. My Regulator fuse was blowing at first at higher speeds. Now it just blows when I turn the motor over.

Here's a link to my post in case anyone needs details

http://forums.luvtruck.com/viewtopic.php?t=14540

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1980 Luv 4x4 with a 5 speed tranny.



"When all else fails, follow the directions".

Drove it around the block and popped the VR fuse again. Pulled the fuse and got to looking at it, seems I had a buss box full of AC rated, 15A, fast blow fuses, and that's what I'd stuck in there. I pulled them out of a box in the truck in the dark, in the rain, with only a winder flashlight to identify stuff. That was a gotcha' I wasn't expecting.

Duh. As if I haven't made enough of an idiot of myself on this board. I'll pick up some DC fuses in the next day or two and see what I get.

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

Don't stress. S$!t happens.

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OK, I'm over it. Where's the beer?

I have a series 10 manual and the series 5 wiring diagram in pdf, but I would sure appreciate it if someone would check their series 8 manual and confirm that this drawing is correct for a '78. Specifically I'm interested in the doubled up BY wiring at the ignition switch (pins 2 and 5).

Thanks in advance

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

I am replacing my Voltage Regulator. Its only $34 on my local Napa store. There is a werid little resistor looking thing that plugs into it.
I am bringing it with me to the auto supply. Check out my picture:

Yes. my 8 manual shows the BY wires the same way. I think both are hot when key on.

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OK, I'm over it. Where's the beer?

Thanks ron I'm going to take one of BY legs and use it for the power for a relay for the accessories. My ignition switch has only 3 positions, OFF, ACC and START and they are set up in a clockwise configuration. Key in and straight up is OFF, one click = ACC, one click + bump = START.

Zane, the capacitor is for radio interference suppression. Not a big deal if you're running a modern spark plug. Mine's missing...Ahah! The cause of all my electrical woes...or not. You've also got a different style plug than I have, mine is rectangular. I have a local parts place that is usually cheaper and uses pretty much only Echelin or Bosch electric stuff. I think they quoted me $43, and a special order for mine. I haven't checked prices or availability at NAPA.

I discovered the stereo I put in is mysteriously tied in to the wiper circuit, so I'll prolly pull it until I figure that out. It's a bit more of a mess in the cab than it is under the hood, but I guess that's to be expected in a truck as beat as mine is...

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

there is a switch here with key for $15 big jims in town has it

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My old but now gone Luv...

Nukeday, thank you for the info. I couldn't find that part in my both my clymer and Haynes manuals. Kinda of a strange componet, but I guess if it interfered with the radio, it be good to have.
At my Napa Store, the first Regulator did have the rectangular plug, they had to order the one with the round plug from a nearby store.

Have any of you replaced your switch? Will i have to splice in the new wires or will be like the stock, just some copper contacts that the plugs into the wire harness?

My Accessory position never worked, so when the regulator is in and that doesn't solve the problem, then at least all I need is the ignition switch.

Check the new Regulator versus the stock one. The new one is a lot shorter! If anyone has replaced the ignition switch, let me know, I want to see how that hooks up.

Unscrew the bezel off the front of the switch, and unplug the plug from the back.
There is a metal guard around the switch, but mine had already been bent all up.You may need to take the two screws out of the dash pod to not bent the metal and get the switch out.

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OK, I'm over it. Where's the beer?

I already have the old one out, its in the last picture. LOL I want to know if the "after market" switch hooks up like the old one, that all.

Ok.

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OK, I'm over it. Where's the beer?