Depends on which fan speed you want to have on all the time. High speed would be powering the Brown/Tan wire. Medium/high would be powering the light blue wire. Medium/low would be powering the light green/light blue wire. Low would be powering the Tan wire. The unit is already grounded, You would just need to run a wire direct from 12v ignition source to switch, then switch to whichever wire you want. These would be the wires going TO the resistor. Running direct power to the motor itself would just give you high speed all the time as theres nothing to resist the voltage and would draw a ton of power as you would be bypassing the blower motor relay. Don't do that.

 

High is perfect for now. Is there not power to the switch already I can pull from?

 

At the switch (5 wires) for ’98 the dark green should have 12v power when the mode slider is in any position except off (key on). Jumping from that to the brown/tan terminal should get high speed. That will also bypass the resistor & trigger the (high speed) relay.

 

Perfect, thank you!

 

To follow up. Thanks again. It ended up being a lose connection at the control switch output (on the right side) I was getting .5V on the green wire. A little bending and its connected tight again.

 

edit...2001 Jeep TJ Sahara

 

For your 2001 the circuit is completely different than the OP’s 1998 so will be different than what I posted above.

The fan speeds since 1999 are controlled through the ground side of the circuit. Yours is apparently grounded somewhere between the motor & the mode selector switch which is the one with the vacuum lines & the 3 wire connector. The speed switch (5 wires) is in the circuit between them.

Remove the panel & see if you can see where a wire has been added or more likely where 2 existing wires are now connected (jumped) together.

The ground wire for the circuit is the black one at the 3 wire connector. Depending on whether you can now change speeds with the speed switch or if it is on high (only) whenever the key is on that black wire may be jumped to either the dark green wire also at the 3 wire connector (if can change speeds) or jumped to the brown/tan wire at the 5 wire speed switch (high speed only).

Here is a link on troubleshooting the entire circuit which should help you getting it working properly after removing the grounding wire, however it is set up now.

Also here is a diagram of your factory circuit from the FSM (assuming you have a/c), if not the fan circuit is basically the same.

TJ Wrangler Auto Electric Help Regarding The Blower Fan?

 

The switch is fairly easy to replace, the wires plug onto the back.

 

Then follow the brown/tan wire from speed switch to resistor &/or blower motor.

If you read the info in the link I posted you will see that most of the "not running on any speed" is caused by melting at the mode 3 wire connector. The speed switches rarely fail & usually bad when only one or maybe 2 speeds do not work.

Always best to troubleshoot before buying/installing parts.

 

Thanks. I just pulled apart and spotted the issue like you mentioned. The brown wire has melted on the 3 speed. Looking at the other thread, can I assume a fix is to cut away connector and attach directly using a wiring tube cover? I didn't see anywhere that a wire was spliced to bypass the speed switch (currently working high speed high heat) . I attached a pic of the blower area ...looks to be a wire spliced there. Again,

appreciate any help.

 

Thanks for including the photos, it really helps figure this out.

It looks like the (added) grounding wire is the one in your last photo on the far right. I see it appears to be tapped into a wire with that red tap. I can’t tell in the photo but guessing it is tapped into the brown/tan, or it may be black/tan (high speed) wire at the resistor. If so, just unbolt it & see if the fan stops.

If so, you are halfway home. Now to the fix.

The melted connector in the 1st photo looks to be the A terminal which is the grounding wire for the high speed. It seems that with only that wire damaged you would be able to get the other 3 speeds. Maybe not having high was the concern for the previous owner so the “repair” that you now have. If you remove the added ground wire & plug that melted connector in you should have speeds 1-3.

If good so far you only need to get that one wire connected to the switch. You can certainly cut all 5 wires & connect them all individually to the switch. That is often done at the 3 wire connector when it melts. If you go that way, be sure to mark each to be sure they go back onto the correct switch terminals. The terminals appear to be pretty close together so if there is any chance the terminals might touch each other they should be insulated & using shrink wrap rather than electrical tape is advised since tape may melt from the heat there.

Another possibility might be to cut out the section of the connector that has the melted wire. Then you should be able to plug it in & only have to cut the bad wire back & add a terminal end & slide it back onto the switch & it would be well insulated too.

See how far that gets you & report results.

 

Yes you can, I've ran my blower off a toggle switch for years. Just hot wire it a source that us always hot. Best to use a toggle switch with a light on it