Tracing the temp gauge wire

[dogsofwar]

I've got an 85 blazer, 305, and I'm trying to clean up all the wiring that the previous owners have put on this thing. All the gauges work except the temp gauge, and there was an aftermarket set that was half-way hooked up. I removed that, but need to know where the factory temp sensor is supposed to be? In the water neck I have 2 things that I have no idea what they are. One is a large hex shape with a button on the top, the other looks like it could be a temp sensor, but it has a spade on top bent over.

 

[Dogman12]

There should be a sending unit on in the drivers side head near the exhaust manifold towards thw front. The ones near the themostat should have been for the computer controlled carb. The factory wire would have been green. Hope this helps

 

[dogsofwar]

temp wire

I'll check tomorrow, there is a sending unit there for the aftermarket gauges so I'm good on that one, I'll have to try finding the wire.

I did find a wire that appears to be stuck under the valve cover, tried pulling on it and it looks like the valve cover is bolted on over it Don't know if it was green or not, it was dark colored though.

 

[Dogman12]

Your truck came with gauges? the wires for the gauges go through the firewall near the fuse block. If you check at the fire wall you should be able trace it. I would remove the wire either way if it has a terminal on the end that could fall off it would help anything. If I remember the alt. has orange wire and oil pressure is brown. Mine were all messed up by PO also.

 

[dogsofwar]

temp wire

Yea, I think the gauge wasn't working so someone had the brillant idea of adding in more gauges instead of fixing it, but then didn't even hook them up.

I'm missing all of the wires that come from the water neck, I am presuming that one of these went to the carb connector on the top passenger side, but where did the other one go? This has headers on it, so any sensors that came from the exhaust are long gone. Should I try and swap in a non-electric carb?

 

[dyeager535]

Does the carb have a connector on the drivers side front? If not, it's not an "electric" carb. If it does, you need to swap carbs.

 

[Dogman12]

Maybe I confused you, the sender for the temp is screwed into the head it has nothing to do with the exhaust manifold, are you trying to hook up the factory gauge or after market? Factory gauge is one wire from the engine bay through the fire wall to the gauge, the ground should be from the gauge to a common ground behind the panel. There should be a big gromet on the passenger side firwall that goes behind the glove box. Check these wires if they dont go to anything in th engine bay PO already took out the computer controlled carb etc. If so you could pull these and the old ecm from behind the glove box and clean up some wires.

 

[Dogman12]

I hope I did not make this more confusing, I have an 85 that came with headers and an edelbrock carb. It took awhile to figure out the wiring and hoses, alot of the emission stuff becomes useless when the headers go on, the air pump and I think it had an o2 sensor, so if all this stuff was removed and the carb was swapped for a non computer you probably have alot of wires going to nothing. Does your distibuter have a vacum advance, a vacum line from the carb to the distributer, if it does it is not computer controlled. Fun stuff! I yanked all mine and put in a fuel injected 350 and am trying to get it running wright. If you get a repair manual from the auto store it will give good pics of differnet years and you can figure out what your had and what is been removed. Also if the ground if off behind the dash the gauge will not work they do get loose. Its easy to pull the panel and gauge cluster if you un hook the speedo cable from the t-case it will give enough slack to look behind the panel. sorry so long.

 

[dogsofwar]

temp wire

It does appear to have the electric carb, just no wires for it. I'm trying to get the factory gauge to work, and eliminate all extra wires that the PO had in it.