A/C blower keeps blowng the fuse :(

Any ideas what could be causing this, the fuse for the blower keeps blowing, not sure why this is happening, anyone have any idea??

More info please....

Well, the moment i turn on the AC, in any setting, the fuse titled blower in the fuse box blows and goes out.........it is driving me nuts.....

tcm glx said:

Well, the moment i turn on the AC, in any setting, the fuse titled blower in the fuse box blows and goes out.........it is driving me nuts.....

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I bet the blower motor is giving too much resistance, I'd take it out and try greasing the shaft. If that doesn't work I'd replace it, thats what I ended up doing. Only like $25 at a local auto parts store.

BigBlackHeep said:

I bet the blower motor is giving too much resistance, I'd take it out and try greasing the shaft. If that doesn't work I'd replace it, thats what I ended up doing. Only like $25 at a local auto parts store.

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The blower motor was only $25?? Really?

tcm glx said:

The blower motor was only $25?? Really?

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Yeah its called like a unimotor, I got mine at O'Reilly's and it was I believe $23.xx, IIRC. I've never been thrilled with the way it's moved air but it is just as good as my OEM one was and much quieter(motor-wise).

It can be the blower motor or the resistor pack, but in many cases it is a short in the wiring harness. My 90 XJ was doing this, even after replacing the motor and resistor pack. It seems that it is common for the wiring harness to get pinched somewhere in the sheet metal behind the dash (somewhere to left of heater control). I never found the actual short, but mine ran OK for years after reaching in and fiddling with the wiring harness to reposition it and put some slack in the wiring harness that attaches to the Heat/AC controls.

RMD said:

It can be the blower motor or the resistor pack, but in many cases it is a short in the wiring harness. My 90 XJ was doing this, even after replacing the motor and resistor pack. It seems that it is common for the wiring harness to get pinched somewhere in the sheet metal behind the dash (somewhere to left of heater control). I never found the actual short, but mine ran OK for years after reaching in and fiddling with the wiring harness to reposition it and put some slack in the wiring harness that attaches to the Heat/AC controls.

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Where in the harness should I be looking for this pinch.......inside the XJ or under the hood.....and then specifically where..I am desperate guys, someone plzzzz help!!

bump

Un plug blower motor under hood & try turning the blower on while disconnected. Fuse doesn't blow it's the motor, fuse blows it's something else. Check the wiring by resistor block under dash on passenger side, make sure that is not pinched. Also disconnect that plug & do the same test as the blower. Check the wiring around the dash controls for the heater. If you have changed the stereo, check the wiring for the heater is not pinched by the stereo & that no wiring from stereo is grounding on heater switch & controls. These are the most likely to cause your problems.

alfman said:

Un plug blower motor under hood & try turning the blower on while disconnected. Fuse doesn't blow it's the motor, fuse blows it's something else. Check the wiring by resistor block under dash on passenger side, make sure that is not pinched. Also disconnect that plug & do the same test as the blower. Check the wiring around the dash controls for the heater. If you have changed the stereo, check the wiring for the heater is not pinched by the stereo & that no wiring from stereo is grounding on heater switch & controls. These are the most likely to cause your problems.

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Thanks aflman, undid the resistor block (which i have replaced 2x already, but unfortunatley with used pieces..) and so far it is working, of course only in Hi...I will keep you all posted...thanks

Does the fan give you any problems in the Vent or Floor position?

Slo-Sho said:

Does the fan give you any problems in the Vent or Floor position?

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Sure does...

I don't know exactly where since I never identified the location of the short, but I mis-spoke when I said to the left of the heater controls -- it was the wires from the heater controls heading to the passenger side (towards blower and resistor pack). Access through the radio/heater opening from inside the vehicle.

Well at least your fuse blows. If I run my AC, my fuse gets super hot, literally melts, and burns up with a nice puff of smoke. I cannot figure it out for the life of me.

In your case, it sounds like the resistor pack was the problem.

RickyN29 said:

Well at least your fuse blows. If I run my AC, my fuse gets super hot, literally melts, and burns up with a nice puff of smoke. I cannot figure it out for the life of me.

In your case, it sounds like the resistor pack was the problem.

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Haha, I just came across my own post searching again for information.

Anyone have any further info? My fuse melts, puff of smoke, and the radio cuts out intermittently right before this happens.

I had this problem once, turned out to be my starter relay near the battery.

ocalajeeper said:

I had this problem once, turned out to be my starter relay near the battery.

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What would the starter relay have anything to do with the blower motor circuitry?

ocalajeeper said:

I had this problem once, turned out to be my starter relay near the battery.

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WOW, tell me more. I am sick of this issue!! What would the starter relay have to do with it? Also, which one is the starter relay and how did you come upon the conclusion that this was the issue.....

There really is no correlation between the starter relay and the HVAC wiring. So I wouldn't bother looking into it. (Unless poster knows something I don't!)

I just replaced the blower motor ($26) turns out the one in there was aftermarket and didn't appear old or worn at all. The situation (melting fuses) is still present. I have narrowed it down to the blower motor wiring. The compressor clutch and related items are not the source of excessive draw. I believe there is simply a poor junction at the fuse box. I am rewiring mine so that the "Blower" circuit (which includes the compressor clutch and other items) only trips a relay (40amp) and there will be a 10 ga wire feeding the system instead. (Fused of course at 25 amps) Hopefully this will rectify the problem.

For others interested, on mine, a 90, I am looking for a Violet/Yellow wire coming from the fuse box to the HVAC control module. This wire will be cut and connected to pin 85 on relay. Pin 86 will connect to ground. Pin 30 will be a 12v+ connection to my secondary fuse box (aftermarket) fused at 25 amps. Pin 87 will have the new 10 ga wire which will run to the HVAC control module (replacing original Violet/Yellow wire).

I should note that I have no way to determine DC amperage draw, but the fuse itself becomes too hot to touch, so I am assuming that draw or inadequet wiring is the problem.

If the problem persists, then I will begin replacing the wiring from the HVAC control module to the blower motor unit. (However, this wiring appears to be fine)

EDIT: Wait, I have to confirm that Violet/Yellow is ignition switched. If it is constant, than a relay will not be required and it can be connected directly to my aftermarket fuse panel.