Rear A/C-heater Blowing fuse

[aballard5]

Hello all!

I have been reading the forum for a while, but this is the first time I've posted.

I have been experiencing a problem for quite some time in my '03 Sport Trac with a fuse blowing every time I turn on the A/C-heater at the back of my center console. On the rear of the console, I have two vents at the top with some controls below it, which consist of a switch of the left side to toggle between upper and lower vents, and a switch on the right for three speed settings for the fan. There are also controls in between the two switches for the radio, but those seem to be working just fine.

When I first noticed the rear fan was not working, I looked at the fuse diagram and found a 5A fuse at position 31 in the panel located on the diver’s side of the dashboard. I pulled the fuse, saw it was blown and replaced.

If I start the truck, then turn on the rear fan, blower works just fine, but the fuse will blow again on the next start, or it will automatically blow on the first start if I have the blower on when I start it. Everything I have found on the internet seems to indicate a grounding problem, but I don’t know how to diagnose. Does anyone have a suggestion? Thanks in advance.

 

[bdmaash]

not sure if it's a grounding problem unless the supply to the fan is grounding (shorting) out.

If the supply is grounding out, then if the blower is unplugged it will still blow fuses.....so maybe disconnect the blower and do the test.
If the fuses stop blowing then change the blower motor, or figure out what's wrong with the motor that's causing to blow fuses.

 

[aballard5]

not sure if it's a grounding problem unless the supply to the fan is grounding (shorting) out.

If the supply is grounding out, then if the blower is unplugged it will still blow fuses.....so maybe disconnect the blower and do the test.
If the fuses stop blowing then change the blower motor, or figure out what's wrong with the motor that's causing to blow fuses.

Thanks bd...I will try and get to the blower this weekend to test your suggestion. I appreciate the reply.

 

[STrac4me]

You should be able to check out the circuit with a multi-meter. With the truck powered off verify that there is no voltage present at the fuse you refered to. Put the meter in the ohms setting and read across the circuit. If the circuit is shorted in any way you would read zero (0) ohms or very close to it. If the fan is accesable you can read the fan by itself and see if it has a problem. The only way for a fuse to blow is to have a short, ground, or the current draw is too high due to binding or something like that. Good luck!

 

[Dead_Goldstar]

I have a 2005 Ford Exp sport trac and there is two levers on the back of the centre console my fan speed switch is not working in the 3 positions how can I check this to see if it's the switch. The front heater switches work fine is there a rear blower motor and what fuse would i check to insure it's not just the fuse.If anyone has any suggestions please let me know.

 

[aballard5]

Hopefully you will find out that it is just a fuse. I'm not certain if the fuse panel for the 05 is the same as my 03, but the fuse for my rear heat/ac is located at position 31 on the driver's side of the dashboard.

I still haven't figured out exactly what is causing my problem, but I did notice that the fuse doesn't blow if the switch is in position 1 or 2. If I move it to the highest position at 3, the fuse blows everytime within seconds. This leads me to believe that my switch is faulty.

 

[NUFX]

You should be able to check out the circuit with a multi-meter. With the truck powered off verify that there is no voltage present at the fuse you refered to. Put the meter in the ohms setting and read across the circuit. If the circuit is shorted in any way you would read zero (0) ohms or very close to it. If the fan is accesable you can read the fan by itself and see if it has a problem. The only way for a fuse to blow is to have a short, ground, or the current draw is too high due to binding or something like that. Good luck!
AC & Heater Control

Thanks for this, I will relay this info to a friend on who is currently figuring out the same thing too. Thanks again.