Working on the Valve cover, found a mystery wire
 

Not sure if this falls under electircal, since its not an issue of the wires not working.

While working on the truck last night I found 3 wires and their termination clip all taped to the AC Compressor Bracket, not connected to anything. The wires run down the top of the engine just inside the Valve ccover in that grove, and are attached to the block with Clips.... any idea what this is supposed to connect to?

Thanks in advance

Does your temp guage work? I seem to remeber the temp sender is on that side of a SB

what color are the wires? Some trucks had 2 temp senders on each side of engine one for the guage & one for the temp light in the dash. If your truck is a fact air truck there should be a small solenoid on the side of your carb that idles up your engine when you turn your a/c on. Hope this helps you out.

Both are good suggestions, i will run the both down. I do not ahve a guage cluster, but it could be the dummy light.

I will have to check on the carb solenoid too. would that run directly to the compessor, or somewhere else, I assumed my wires ran to my fuse panel but if it is the ac stuff I could probably trace it back to the the unit somehow.

Anymore suggestions would be welcome!

None of these trucks ever came with 2 sending units. Not originally anyways. The only original location for the temp sending unit for a small block 67 - 72 truck is in the passenger side head between #1 and #3 cylinder exhaust ports.
This may be for the vacume advance delay crap that they had as primitive emissions... Not sure since I have very few details, I think that was mounted on the passenger side of the intake with a relay or something on the firewall.

Thanks again guys.

[QUOTE=Longhorn Man]The only original location for the temp sending unit for a small block 67 - 72 truck is in the passenger side head between #1 and #3 cylinder exhaust ports.

Or in the intake manifold near the oil fill tube in the case of a 67 327. ;)

Isnt #1 and #3 cylinder exhaust ports located on the drivers side of the engine?? ;)

My temp sensor is on the drivers side from the factory. 1971 307 V8

LOL...yes. I ment drivers side..the caddy engine has #1,3,5,&7 on the passenger side. I had it pictured in my head properly...just didn't word it correctly.
As for in the intake... I've never seen that, but my 67/68 hands on portion is minimal.

Trucks equipped with a TSC system did have two temp sending units. Gauge one in D/S head TSC controll on in the P/S head.

I took a look at the wiring diagrams in my haynes Manual. It was late when I got around to it but I think the temp sensors only have 1 wire going to them that I can tell. The one I found is has 3 wires. It looks a lot like the wiring for my alternator, I thought maybe it was pre rebuild and they replaced it, but it runs down the PS with clips there for it.. alternator is on the other side.

What engine do you have? The stock location of the alternator on a SB is on the driver side too. I have a wire bundle that goes down along the valve cover then splits off to hook up to the alternator and the temp sender. 4 wires I think (correct me if Im wrong)

Sb 350 from a 71, thats why I dont think its for that application. I am surprised that it has 2 sending units for the temprature.... gues I am just going to have to go digging for a termination point to see what it is really for.

I have to go back in anyway, the old gasket didnt set right when I replaced the valve cover, I drove it for a half hr last night and it started oozing once the oil heated up o well, back at it.

What is TSC system? and would it be on my box sticker or sales receipt?

Actually its TCS(my mistype) for transmission controlled spark. It has a switch in the transmission, a relay on the firewall, a temp sensor in P/S head and a solenoid on the intake manifold. It shuts off the vacuum advance in the lower forward gears, the temp sensor overrides this when the engine is cold.

I have a stock 3 spd. this sounds more like something you would put in a Auto Tranny.

You are correct.

OK back to doing a hunt and peck for the socket.

Sounds like your truck use to have an under dash A/C unit installed at one time. My 71 has the exact same setup your refering to and it went to the A/C compressor that use to be there when the old under dash unit was installed.

Shouldnt be, I have factory air. but it does look like the same wiring.

Have you checked the connection for power? If so, does it come on when you turn the ignition on, or is it constant? It's sounding to me like an a/c power source, as said earlier. You may be able to simply cut it off at the source and rid yourself of the problem.

My buddy that rebuilds 350s for his Pontiacs of the same era, said it looks like the TCS harness to him. That it is possible when they did the reubuild the harness included that connection although it was not needed. so they just taped it off incase he ever went automatic. We dont know for sure but that is as good a theory as any.

My ole heap has same wires.Do not remember what they went to . Alternator I think , Used to have a six cylinder, Wires were ran a bit different. Than for what is in there for an engine currently. Probably was for an idiot light of sorts and for sure one was for temp gage.

It possibly may be a Engine Block Heater cord...