The 40A feed should be constant. Sounds like you have an open circuit between the fuse and the relay terminal 30. It could be anywhere in the circuit. You'll just have to trace it with a test light or a meter.

Just to test if this is what is wrong you can run a temporary 12V lead to the battery and connect it to pin 30. Just be sure to fuse it.

 

98

 

Guess that means the dash has to come off since that green wire that goes to terminal 30 is buried under there. Any idea where that wire ends up going to?

I'll jumper pin 30 with a wire at least and see if it works like that.

 

Here.....



Make sure you are not confusing the PDC and the junction block.

 

Nope, I definitely checked the PDC under the hood. That diagram will help a lot, I don't which wire is the green wire going to the relay though. It doesn't look like they labeled the colors on some of those wires. Nor are the relay pins labeled. Or maybe I just don't know how to read an electrical diagram. It's been years...

 

Well, I literally tore apart my wiring harness and I traced the red/green wire which goes from the 40 amp fuse at the fuse box all the way into the Jeep. It has power ALL the way through the wire into the car, so I don't think there is an open circuit.

The only thing this leaves me to think is that maybe the fan speed **** on the dash is faulty and not causing the fan to turn on. Could this be the case? If it is the case how can I go about testing this thing.

 

take the dash apart there and teset the switch with a test light for current in and out of it

 

Well I tested the plug that goes into the climate control ***** and none of the wires get power to them at all except one of them but it only gets power when you turn on the dash lights (which means it's obviously the wire that makes the controls light up). No other wires have power though, should they?

 

Okay, maybe you guys can help me with this...

I followed the 40 amp fuse wire (this is a larger wire that is red with a green stripe) from under the hood all the way into the firewall and under the dash. I used the test light and the wire coming from that fuse into the car has power all the time, even when the car is off (like it should). I used the test light at multiple points throughout the wire just to make sure there wasn't a point that it lost power.

Well, underneath the dash the wire has power as tested with my test light. After entering the firewall the wire goes to a big 'junction' plug with a bunch of wires in it. The wire has power on the other end of that junction so I kept following it. I followed it to the next junction which is underneath the drivers side kick panel right where it meets the center console. The red/green wire has power entering this junction, but on the other side of the junction where the wire comes out there is no more power. I'm thinking that perhaps it's the connection on the wire where it goes into that plug? Or is that wire supposed to lose power there?

Lastly, ETexas XJ was saying above that I should have constant power to pin 30 on the blower motor relay. However, this red/green wire that I'm trying to figure out connects to pin 86 on the blower motor relay so are you sure it's not pin 86 that's supposed to have the constant power?

 

I labeled the pins in the pic below. Keep in mind the polarity in this case is not important. 85 and 86 can be switched with no problem. Same for pins 30 ans 87. 87a will not be used.
Also note that ALL POWER to run the heat/fan is supplied from the 40A fuse. The other fuse only allows for operation with the key on.

Power has to flow through the blower motor THEN to the switch in it's search for ground.
Until you get the relay working you won't have power at the fan switch.
In the diagram power flows from the top to the bottom. Places labeled G are ground.

If your 40A feed is going to pin 85 or 86 then someone has screwed with it.

It should be a constant, uninterrupted power source from the fuse to the relay.

 

Well, all I can tell you is that the wire that leaes the fuse block under the hood where the 40amp fuse is is a larger red wire with a small green stripe.

That wire I followed all the way through the engine (tore apart the wiring harness) and into the cabin of the Jeep. It then goes under the dash and eventually ends up at pin 86. I extremely peculiar because according to your diagram pin 30 is labeled as RD/LG which I assume means red/light green which is indeed the wire that leaves the fuse box.

However, on my relay pin 30 has a larger all green wire and the RD/LG wire is going to pin 86 instead (it's not getting power anyways).

So, call me crazy but I'm starting to think maybe someone who owned this before was trying to trouble shoot it, removed the wires from the relay, and put them back in the wrong spots.

Now I could switch them around and make them correct as per the diagram you posted, but of course that wouldn't change the fact that there would still be no power to pin 30. The RD/LG wire is the one that seems to be the culprit. It has power all the way into the cabin but it loses power shortly after one of the junction blocks (a huge plug with a ton of other wires in it). I don't think it's a bad ground or anything because the wire does have power up until that junction block, it's on the backside of that junction block where it exits that it has no power apparently.

Thanks for labeling that diagram for me, you have been a tremendous help. I was confused about which pin was which.

Anyhow, I'm slowly getting to the bottom of this. It just sucks because everything is packed in behind the dash so tight.

 

I'm thinking you have a broken wire/bad connection in the RD/LG and someone has attempted a rewire/repair and made it worse.
Pin the relay as it shows in the diagram and repair the RD/LG and see if it works. If the blower motor and resistor are ok then it should.

Hope I can help. Being cold SUCKS!

Where ya at anyway?

 

I'm in Portland, OR so it's mighty cold right now!

I'm guessing you're right about the wiring. From what I can visibly tell it looks like there was likely a bad connection in the wire to begin with and instead of fixing it the right way the previous owner likely tried to rewire things and screwed it up even more. Fortunately I think I may have found the bad spot on the wire so tomorrow when it's light out I'll try and fix this once and for all.

I'll let you know how it goes!