[mcfam]

03 f350 6.0 4wd xl
Fuse 28 eatc( I don’t have)/ front blower relay coil keeps blowing. Changed relay and didn’t fix it. It will run for a while every time I replace fuse and then all of sudden just blow. Nothing has been changed on the blower controls. Anybody got any ideas on this and maybe a good wire schematic for that circuit so I can trace the wires.

 

[RMTZ07PS]

Found this doing a quick search. Also there is a search bar on this sight and could help. Haven't figured how to post the link from my new android phone so screen shots is all you get lol.
Well I can't even get this right, stand by.

Join Date: Feb 2008
Location: BC
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Well problem solved. Seems the fuse boxes differ a bit from year to year so fuse #28 on an 03 may be another on later models. Frayed trailer harness blue and green were rubbing under the hitch mount. Also, there was corrosion on the electric brake pin in the housing of the external plugin which needed cleaning. Everything back to good now and no fuses blowing.

The funny thing about this thing was that fuse #28 would blow sometimes with key in the on position and other times I may just make it down the road a few minutes before a blow. When it was working the fan and ac were perfect and smooth with all resistor levels in check. I can't figure why the shorting out back in the trailer wiring end would blow my EATC/ front blower relay coil fuse though? I do have a electric brake unit hooked in to my dash, a Prodigy model that plugs right in...it gave me no indicators of trouble either. My XL is all manual so no EATC.
DMH

 

[mcfam]

Any help would be greatly appreciated!!

 

[jokester00]

A quick search found this with some good wiring diagrams and T/S. make sure everything is the same for your '03.

2004 f350 Fuse 28 keeps blowing. EATC/Blower fuse. I have replaced blower motor, resister, relay under hood, and (justanswer.com)

-jokester

 

[mcfam]

Did a quick check for a short and couldn’t find anything. Disconnected the ac high and low pressure switches and put a new fuse in. It worked for a whole day on the road, blew in the middle of nowhere and it was cold. Stuck a new fuse in but it blew within a couple of minutes, so I gambled and threw a 20 amp fuse in and it has held for a couple days now. This circuit looks like it is just control wires, nothing with a load on it. Anybody have any ideas to fix this right?

 

[jokester00]

Did you read the whole link I sent above? It's got some good step by step instructions on how to troubleshoot this.

-jokester