A/C Wiring Harness Help (Fan Speed Dial wires)

Year 2000 TJ. I just purchased, it's had many owners that apparently spliced a wire here and there to run accessories for who knows what. In any case, I recently installed a new Heater Core and AC Evaporator in the HVAC Box and putting in a new Dash Panel Switch unit. Before I button everything up, I wanted to get these wires fixed, the wires that go to the AC Panel Switch, specifically the Blower Motor Speed Setting dial.

There are 2 Lines that weren't attached to anything, they just had electrical tape on the ends. One is a BROWN Wire with WHITE Stripe coming from the main harness, not attached to anything. There is also 1 of 3 small PURPLE wires on the plug (1 has a larger Blue wire attached) that is not connected to any of the lines coming off the main harness. Lastly, there is a LIGHT BLUE wire coming off the main harness, that is attached to a BROWN wire on the plug, is that something that might need correction?

Hoping someone can take a look at this HOT MESS and advise what corrections or connections might need to be made. I'm going to use elec tape and cover all the jumper cuts and clean it up, but want to make sure right connections are in place.

Photos attached, sincere thanks for any help. I also just installed a new AC Compressor, new AC Lines, New Condenser, so I really would like this to work after all that labor. The wires are the last frontier here.

It does somewhat, thanks Charles. Are the LG, LB, TN referring to the colors of the lines? Light Green, Light Blue, Tan? If so, wondering why the number 1 line on the resistor changes from TN to WT on the switch, is WT white? I don't have a white line.

CharlesHS said:

-In the front of the FSM section of 8W there is General Information for the wires colors on 8W-01-4.
LG is light green, LB is light blue, WT is white and TN is tan.
Line 1 on the resistor changes from TN to WT when it passes thru C205.

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Thanks Charles, I don't have a manual but will acquire one or download.

In the meantime, I decided to make a few cuts to clean up the mess the POs had made in there and ordered a new plug kit on Amazon. Please, can you take a look at my sketch, see if I have captured it correctly,

Fan Speed Switch
TAN (TN) = Speed 1
LIGHT GREEN (LG) = Speed 2
LIGHT BLUE (LB) = Speed 3
BROWN & TAN (BR TN ) = Speed 4
DARK GREEN = Input coming from the AC Heater Plug next to the vacuum module.

AC Heater Control Switch
BLACK (BK) = Input
DARK GREEN = Output to the Fan Speed Switch
LIGHT GREEN (LG) Thin Wire = Dial Lighting

CharlesHS said:

You should be able to use the schematic that I posted above and the wiring colors to identify how to wire your fan relay, mode control switch, speed switch and resistor block.

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Charles, when I take a multimeter to the Black input wire on the side of the vacuum switch, about how many Volts should it be reading?

CharlesHS said:

You should be able to use the schematic that I posted above and the wiring colors to identify how to wire your fan relay, mode control switch, speed switch and resistor block.

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Charles, does C1 ( Plug for the Fan Speed Switch) and C3 (Plug for the AC Heater Control), use the same power feed, the line coming from #8 Fuse at RUN A22 (the RD/DG) 20gauge wire? Reason I ask, I spliced C1 E and C3 B together with the power feed coming from #8 Fuse, but right now when I turn the AC Heater Control to "ON" position, it blows the 40A Fuse for the Starter at the Power Distribution Center BATT A0. Gone thru 2 fuses. Before I waste another $4.99 on a 40A Fuse, was hoping you might be able to help.

Q: Should there be a separate power feed source for C1 and C3?

If that's not what is blowing the 40A fuse at BATT A0, might be something with the blower motor itself, the wires on it the PO had also spliced and it's a little bit of a mess.

CharlesHS said:

According to the schematic C1E and C3B are joined in the harness somewhere.
C2 is powered by Fuse 8 (10A).
To blow the 40A fuse there is a high amp draw or possibly a short to ground.
You are going to need to trace the wiring and verify what it connects to and what the previous owner did to your wiring to resolve this problem.

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Charles, my sincere thanks again! Through careful study of the wiring diagram 8W-42-3, multimeter and an EE friend of mine who elaborated on the Relay (Solenoid that opens/closes the connection) I was able to trace the problem to the C202, and socket A1 (20RD/DG) it had literally "popped out' of the terminal and hence no power from that side going to the relay on socket #1 on the Blower Motor Relay, to open the circuit with #4. I now have the fan running, Heat & A/C on tap. I feel that one thing to add that maybe helpful to others that research this problem is reference to the Service Manual (FSM) and Section 8W-80 Connector Pin Outs. Using those made it much easier to understand "what is C202" it's the gray plug at the terminus of the wiring harness at lower left of the front dash, and the locations of each wire and where they are going. So pages 8W-80-4 thru 8W-80-13. Understanding the schematic on 8W-42-3 is much easier when also looking at those pages of Plug (Pin Out) diagrams.

bandit__tj said:

Hi CharlesHS, BobbyA1,
I hope you guys don't mind me jumping in on this post--I figured my question is similar to the above thread (wiring to the HVAC control panel in my 2000 TJ).

I recently had some mice get into my dashboard and found that my HVAC fan/blower was no longer working. This led me to remove the dash/panels to clean out the nest they made right behind the HVAC control panel, and I found that they had chewed through some of the wires (which is what I'm hoping explains the non-functioning HVAC). I've attached a picture below.

Thanks to the diagram above, I can identify the damaged wires as
1- C2 RD/DG wire (from Fuse 8)
2- C2 BK
3- DG wire connecting C1 to C3

I figure I can replace #3 (the DG wire connecting C1 to C3)

Question: any advice for what to do about the other two wires? Do I need to replace the entire harness, or perhaps splice in some replacement wire? Or just cut out the damaged parts and pull on the slack in the rest of the harness?

Thanks for any help!

View attachment 290257

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Sorry for the late reply, hadn't been on the forum past couple weeks. I would wrap the larger green wire (12GA?) wire with elec tape. For those smaller (16GA?) wires, the 2 on the plug, if it were me, I'd carefully cut above the plug what you have left and put in a new section of wire. I guess you could also try to just redo the plug and remove the Blue and RD/DG wires but redoing the terminals inside the plug can be a real pain.