Back driver's side of the block, next to the valve cover as Chooster said. Should have one wire running off of it. You WILL leak a little more antifreeze replacing it.
Any idea what color that wire is that goes to thermostat? I found a charred red wire dangling with a connector on it by mine and nothing connected to thermostat. Bought a new tstat and want to make sure I get everything hooked up right. Is there a way to check the wire going to t-stat? Does it have a charge? Continuity? Resistance?
Temp sensor is different than the thermostat. Thermostat is in your water pump and doesn't have a wire, it physically senses the water temp and opens up when appropriate to allow water to cool the engine. Temp sensor is just a resistance-based thermometer that sits in your head's water jacket and sends temperature information to the temp gauge. The plug is just a little cap, your temp sensor should just have a little nipple top that it plugs on to.
As I mentioned, to test whether it's functioning or not, simply ground the plug on the wire to something like the frame or the block. Watch the temp gauge soar and then call it good. There's a web page out there with resistance measurements vs. temperature: John Strenk's gauge troubleshooting page but it seemed overly PITA, so I just went with what it was reading. Every CJ temp gauge seems to behave differently, it's more the trend that matters. For example, mine typically goes up to about half on the highway, then settles at about 1/4 in city driving. If it were to go above 1/2 on the highway or 1/4 in the city, I'd start to get concerned.
If memory serves me, it was an orange wire, but Matt may be right. I don't have my Jeep in front of me to check.
You know... without even looking under the hood, I think I remember a dangling wire with an elbow connector toward the back of the block. I bet when it registered the other day it may have dangled and grounded out temporarily... if I'm lucky. I'll keep you guys posted.
Also- see this photo below. Do I have the two smaller tubes coming from the thermostat backward? The PO had it set up this way and it looks awkward.
This is a V8, but I used a 258 harness, so the plug and wire color should be correct.
Thanks for the info.
Matt you may be the winner on this one. What I thought was red is actually charred purple and covered in oil!
Thanks again. Hopefully I can get this temp gauge working and the new thermostat in tomorrow.
Is there any thing that typically goes wrong with the temp sending unit aside from bad wiring. Does the unit itself usually hold up or should I just get a new one since I am replacing thermostat as well?
Good to know. I'll be sure to switch them. I was wondering why AMC would have made them that funky.
Also- (may be related to the hose switch)- I'm leaking coolant from one or more hose connections. Is there a sealant I should have put inside the hoses at the connection points to the engine? When I asked the auto parts clerk he looked at me like I was crazy. I used Blue gasket sealer on the gasket for the thermostat, but no sealer on the hoses themselves. I tightened the clamps pretty tight, but didn't want to overtighten them
You probably shouldn't have to use any sealant, but mine leaked terribly without it. I went with black RTV, just a tad, on the metal ports - engine block, manifolds, heater core, etc. Let it set up for a few hours with the hoses on there, just finger tight on the clamps, then after 6hrs or so gave them another turn or two to tighten them up. The RTV takes a while to cure, so that's why I let it sit. Don't let it sit and it just pooches out when you clamp down.
Hey guys- revisiting my old thread. I know I need to reverse the two criss-crossed radiator hoses coming from around the thermostat housing (see pics).
If I just switch these two pictured here, do I need to switch anything else, or will that work fine? Does it matter which ports the hoses go to and from the firewall for the heater? It currently goes from the thermostat housing to the top port on the firewall.
Thanks! Replacing the thermo housing with the 4.0 one to add an aftermarket mech temp gauge to fix my questionable temp issues once and for all!