Thanks again for the help. I under stand the knee issue my wife has the same issue. SO far today all has worked well. There has been no issues. I did pull the relays out of the fuse panel and the one unmarked relay that the manual said not used, I replaced with a new relay. Who knows nothing else has worked.


what I know today is that the blower has been off and not on unless selected on. I did stop by a local shop and asked if they could puss the fuse panel to check possible water/short damage and they would for a small amount. of only $300.

 

Ok, this issue sucks when it happens.

Pretty sure I am having this issue due to the water on my driver's side floor mat (never ever leaked, changed a cab light bulb and.....) after a really heavy rain storm.

Pulling the fuse or relay under the hood stops the blower. Sometimes it stops with key, other times I have to turn blend **** to "off" If it's running and I turn **** to "off" it stops, and won't run when I turn it back "on" Works normal when key is on....

Planning to do the "leave a small heater on the floor" trick.

 

I went through all the wiring diagrams and was leaning to leaks also. However in the fuse box by the driver left knee there are "5" relays in mine. I checked each relay with the diagrams and replaced a couple dont' remember which. However that did not work.


There was a 5th relay on the very bottom of the fuse box I thought was a spare. However I pulled it and the blower stopped. This relay was not listed in the owners manual or shown in the diagrams. I replaced this relay with a new part and I have not had this problem again and my batteries have not gone dead even after a 7 day park period.


I have no ideal how this relay connected due to no diagrams showing and I surrender how it is wired I dont' know. What I do know is that changing that #5 relay on the very bottom solved my problem. What I am thinking is that it is a power switch for the delay timer acc position after you turn the truck off and stay in. It may be wired to a door switch to open the circuit and turn off. IF it has failed in the stuck on position that might be what was causing my problem


Sorry I can't be definitive on this due to the lack of Ford documentation. My truck is the Limited Version 2000 7.3 4WD.

 

Little update:

Also having my "chime" come on repeatedly (the door open while driving / parking brake left on etc on)

Pulling fuses or relays under on the "knee" fuse panel did not stop the blower.

I could hear clicking like crazy, sort of under the A/C vent to the right of the gauges. I took the dash apart. There are three relays under the dash under a cover. Wiggled those some and it stopped, wiggle some more and the blower would start up on it's own then stop again. click click click.

Hoping this is it...

 

Here's the current problem I am having. Whenever I start my truck, the fan comes on full blast. The fan speed is constant no matter what fan speed is set onthe rocker switch. If I turn off the climate control system (with the off switch) it doesn't do anything except shut off the AC. The AC won't come back on with the AC on/off button, but will turn back on if I press the fan speed down on the fan speed rocker switch.

Thoughts? Do I need to have the climate control rebuilt? How do I troubleshoot this issue?

 

some fans have a resistor bank to control fan speed. IF the resistor bank burns out then you will have only one speed. I haven't checked on my F250 to see if it has or doesn't have the resistors. If you do my first place would be to pull and check them.

 

Manual climate controls use a resistor pack, automatic controls do not, they use an electronic module (blower speed control module) to control blower current and hence motor speed.

 

I unfortunately have to jump into this thread now...99 f250 5.4...the truck was stone dead today, driven normally yesterday. Absolutely no power whatsoever after inserting the key. Hooked up the booster pack, got inside and the blower was running, key still in my hand. Drove it, parked it, and the blower stayed on. I make a mental note to check FTE when I get home. On the way home I look down and the speedo is having a little fun dancing between 70 & 100 (kms), it soon gets tired of that and quits all together (ABS light does not come on), that is until I indicate a lane change and the speedo dances in time with the turn indicator... Scanguage registers nothing as far as speed or fuel consumption.
I doubt i'm dealing with two separate electrical issues here, can a wet GEM cause all of these shenanigans?

 

My issues were all due to wet fuses panel under dash, my GEM and panel were fine, just needed to drive out good. Al issues went away, but it took some time.

Turn your climate control OFF when parking truck, fan should not run at all that way, alternately, pull fuse under dash when parked.

 

A wet GEM can cause all sorts of weird things.

 

Don't forget to fix the leak in your windshield to keep it from coming back.

 

YES I had my windshield pulled by safelite at my risk of course and resealed to stop this problem

 

We have a 1991 Ford E350 and we were having the dead battery. Replaced the battery and it was still going dead. I heard the blower going even when there was no keys in the ignition! I'm glad we have this forum as someone else located the source of the problem. It was the "MOTOR BLOWER RELAY SWITCH"! On the passenger side under the hood under the battery and along side the radiator. Ordered one on line, replaced and whala! Works like a charm.

 

Could you possibly show photo? I have been ill and just can't go pulling stuff to find it too weak. Would be great to see exact location and part number.

 

Ordered the part from Amazon (ours 1991 E350 motorhome) https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
My husband and I are not mechanically inclined at all. Once we saw what the part looked like it was easy to spot on the passenger side. The hard part was getting to the screws it was a 8mm size tool.


Location blower motor relay