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CUCV wiring woes

J

jaytee

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Ok so on my 85 Blazer CUCV, I have no working accessories that are powered by the ignition. The starter does not crank when I turn the key. Nada. The headlights, turn signals, etc all still operate. If I unplug the starter relay and hook up a jumper from the positive to the purple output wire that goes to the solenoid, it will bump over. I took this to mean that the ignition switch was bad. I popped off the plugs on the switch. I have 12v juice at both of the blades on the connectors where the red wires go it, one on each connector. I tried hooking a jumper up across the connector from the red wires to each of the accessory outputs and nothing.

Should I still replace the switch? Any ideas? Is there something else that could be my problem? This is my daily driver and between this and the water pump it has been down for two weeks now, I finally have a day off to fix it and I need some help.
 
Ok so I replaced the ignition switch, no dice.

I have no juice on the pink wire circuit, the one that is made hot by the ignition key and controls the fuel pump shutoff among other things.

Any ideas?
 
Are you a member over on www.SteelSoldiers.com ? All military vehicles all the time. If the wiring is still stock then they could talk you through most of it.

If it's 12v then this place is as good as any.
 
Thanks for the info! I'll check it out. My blazer is 12v, but the conversion was done by the PO and it wasn't done right. This whole thing started because I tried to do it right, based on the instructions from that Michigan Fire Brigade .pdf that is so popular. The wiring harness had been hacked up a little bit, and the 2 alternators were both still hooked up, but only one was plugged in. It was pretty ghetto and I wanted it to be done cleanly and properly. Now it just doesn't run.
 
Sounds like you roasted a fusible link somewhere...

Rene
 
Considering I did that myself this past summer I should have caught that. Yep, definitely sounds like a dead fusible link.
 
yeah thats what I thought too, fusible link, but they all look good, I guess I should pull them all out and test them, is there one specifically for that pink wire ignition circuit?
 
ok so its not an open, it looks like a short

no juice at the on the pink, so I hooked up a jumper from the hots at the ignition switch but didn't attach it to the pink, and I got what I expected, 12v

as soon as I plug that wire into the pink, I get 20mv, it drops down

when I unplug it from the hot source, it drops off again to 0.00v. Dead. So, its a short somewhere. Now I have to find it.

Sigh............
 
I bet you did blow a fusible link somewhere. This sounds like mine but mine was easier to find as it was the first fusible link in the 12v supply. Mine didn't look toasty at all, just like all the other 20 year old fusible links.

Bigtrucksmallcid's advice to me was to just start where you had power and follow it until you stop having power.
 
so I figured out that if you pull fuse #20, the "ENG CONT" fuse, then the short goes away. So my draw is somewhere on the back end of that. One of the things it powers is the seatbelt warning buzzer. I pulled that but it didn't solve the problem. The only other things I see drawing power from that are the "water in fuel" solenoid and the cold advance and fast idle temperature switch.

WHERE IS THE COLD ADVANCE AND FAST IDLE TEMPERATURE SWITCH AND WHAT DOES IT LOOK LIKE?
 
So I followed the juice out, disconnected the fuel filter assembly and the cold advance and the draw is still there.

Back to the drawing board.

The only other place that the current goes in that circuit is up to the instrument cluster, and the wires themselves. I'm going to call it quits tonight, tomorrow I will start testing the wires. Hopefully its not up in the instrument cluster I guess. I will unplug it and see if that makes the problem go away.

Thoughts?
 
Sounds like your on the right track. Its all a process of elimination at this point.

However, if you end up disconnecting everything and still have a problem then it's probably in the wiring between the fuse and one of the items you just unplugged.
 
so I climbed under there tonight, tried to clean up the threads that are in the block and get the new SBC bolts that I bought to work. No dice.

The SBC bolts are too narrow for the bolt holes anyway. They have slop. I am glad I dropped the starter when I did, so I could learn that the PO put these stupid SBC bolts in there and ruined the threads in the process, as well as didn't re-install the starter bracket.
I have the proper bolts for the starter now, metric ones, as well as bolts for the bracket and the bracket itself. All I need are the holes in the block repaired. I'm going to start calling around tomorrow I guess and get some quotes for a mobile repair/machinist guy to come by and put heli-coils in for the proper bolts. If none of them will do it, then I guess I will find a shop that will do it and have it towed there.

Or I can sell it. If you want it, come get it, 1000 dollars buys a nice 85 1009 in MD with a strong 6.2 that doesn't smoke or use any oil at all. All it needs is some heli-coils or something.
 
jaytee said:
So I followed the juice out, disconnected the fuel filter assembly and the cold advance and the draw is still there.

Back to the drawing board.

The only other place that the current goes in that circuit is up to the instrument cluster, and the wires themselves. I'm going to call it quits tonight, tomorrow I will start testing the wires. Hopefully its not up in the instrument cluster I guess. I will unplug it and see if that makes the problem go away.

Thoughts?
Click to expand...

Maybe you have fixed this by now, but... I had a similar issue with my truck. It turned out to be a relay that mounts at the bottom of the dash and to the right and above your gas pedal. Turn the key and listen for a click. That is how I found it. I could put a screwdriver in the gap to start it. Kind of a risky way to start it but it proved it was the relay.
 
CUCV2 said:
Maybe you have fixed this by now, but... I had a similar issue with my truck. It turned out to be a relay that mounts at the bottom of the dash and to the right and above your gas pedal. Turn the key and listen for a click. That is how I found it. I could put a screwdriver in the gap to start it. Kind of a risky way to start it but it proved it was the relay.
Click to expand...

That relay can be removed and bypassed when you convert to 12V on the CUCV.
 
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