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Is it possible that a source of a liquid is located to the left of this offending switch? My WAG is that a liquid may be sloshing onto the circuitry, shorting it out during a left turn. Either that or a chafed wire that gets swung to the right and shorted out during the same turn.
It's dry as a bone around every box and wire. Stuff really stays crisp and clean here in California, so it's easy to notice stuff like that. After still blowing the fuse after securing, checking and zip tying the fuse, I was in the yard hanging off the side of the fender pulling and jumping on the bumper like a crazed monkey in the hopes spying some movement under there. I was worried the neighbors might call and have me carted off.
I don't think this is a liquid issue, still thinking its one small wire that's had its insulation chaffed away, something sitting close to a ground source.
WorldCommander use your service manual or EVTM to find the A/C related switches etc as they reside on your van. One should be under the hood in the same general area as the battery and evaporator box, the other close to the A/C compressor itself.
Disconnecting either or both of those components and doing your left turns should reveal if they're the offending parts.
This is NOT as simple as we'd hope it to be----since its mostly an intermittent problem (albeit repeatable in some way) this is one of the most challenging bits of vehicle repair---what to do when all else fails? Despite having tools and manuals occasionally it comes down to old fashioned looking until we find the problem.
Not sure what else I can offer but won't give up until/unless you do!
Did you ever figure out the problem? My 2006 E450 that I just bought is having some blower motor issues. It worked the day I drove it home. But sometime on the trip, I could smell the burnt electrical odor. Didn’t notice if that’s when it quit. Now it won’t work at all. Fuse 13 is good, new relay, 50amp fuse is good, new resistor, tested blower motor when changing resistor, worked. Fan switch at dash doesn’t show any signs of melting. Wires and connector all look good. ??? Could the dash fan switch be bad without showing any signs of overheating? Anything else I can replace? Thanks for the help!
Yes the blower motor speed control can fail without major visual signs. If you smelled odor that means the switch has been hot enough, an inspection will probably show the switch AND the pigtail connector have melted.
I've had this happen on two different E-Series so its rare but not impossible. Here's what can happen:
Boy that baby got hot!
My switch was bad when I got the van.
I seem to recall back in the day, where was a coiled resistor in fords that would get hot, but they seem to have been meant to do so before the switch...
Now that I think about it, they were mounted in the blower housings...
Boy that baby got hot!
My switch was bad when I got the van.
I seem to recall back in the day, where was a coiled resistor in fords that would get hot, but they seem to have been meant to do so before the switch...
Now that I think about it, they were mounted in the blower housings...
That's not exactly correct. The resistor network allow the blower motor to have different speeds. When the blower is running at its highest speed there is a relay bypassing the resistor network--in that situation the blower is turning at its designed speed.
When the highest speed is selected the dash mounted control switch sees very little amperage draw---when on any slower speed that switch passes more current due the resistor network. If you continually run the blower at the lower settings its more prone to fail as my photo shows. For the most part my blower motor runs on the next to highest or "medium" setting so failed switches aren't unexpected.
Wow, I must have got lucky. No sign of burning on either the pigtail or switch, but a new one fixed the problem. For other readers, it doesn’t have to be visibly burnt to still be bad. I did smell a mild electrical odor, so I’m pretty sure the switch was the problem. Funny, I was kinda disappointed when I pulled the dash apart and the switch looked good. Autozone resistor $23.99 and relay $9.99. Napa switch $19.69. Back in business. Thanks for the help!
Sorry to reply to the old thread, was hoping you had found a solution. I have a very similar issue except the fuse blows on every setting except vent and off.
Sorry to reply to the old thread, was hoping you had found a solution. I have a very similar issue except the fuse blows on every setting except vent and off.
What year/make/model of vehicle?
How many miles on it?
Have you inspected and/or replaced the blower speed switch?
Have you inspected and/or replaced the blower speed switch?
1998 ford e350 7.3L, 246k miles. I have replaced that. I found what could have been a short to the AC pressure cutoff switch but had some other problems so got to fix that before I can continue troubleshooting. I started a separate thread with all the info I have about it. Thanks
In this thread, they appear to have solved the issue at-hand with new blower switches. The other thread is probably a better place to troubleshoot the overall issue.
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