87 f-150 blower problem
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87 f-150 blower problem
I have a 1987 ford F-150 with a 4.9 liter in-line six cylinder engine with 250,000 miles on it. ever since we bought the truck in 1990 the blower motor when turned on pulled so much power that the volt guage would go to the red zone. i have done the following things to try to fix this problem: new higher output alternator, new blower motor, new blower resister, bigger battery, new blower switch, checked for air flow restriction, and tested the volts guage. none of this helped with this problem. one mechanic told me it was probally the volts guage but when the blower motor is turned on the turn signals barely flash and the lights go dim. it's a shame because the a/c works great on it, but you can't run the blower to enjoy it. has anyone else had this problem? i would appreciate any suggestions or comments on how to fix this problem.
Mountain Pass
Joined: Sep 2004
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From: AZ
I have an 87 F150 EFI 4.9 123,000 miles, but no blower motor problem. Maybe this blower motor needs to be wired up on its on circuit, not tied in with anything else or check this option out if you haven't already done this.
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I don't want to sound dumb here, but have you checked the grounds? Usually when something draws to much juice when on, its a bad ground. My fuel pump bus fuse kept blowing, had no idea what was wrong, I was going over everything I could think of. Finally, asked a friend who does car stereos and says this is a problem with alot of self installed stereos. They ground is poor so there is a huge voltage draw. So I cleaned the ground by the radiator (thats the ground for that wiring branch) it had a little corrosion but not much. Anyhow haven't had a problem since then. I am not much of a electrical expert, but everything else I am good at. Maybe a wire somewhere in along the motors path has grounded something slightly. Since you have changed the motor, the wiring for it sounds like its the only thing left. Probably wrong, but I gotta try.
CJ
CJ
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Basiclly, start at the switch(hey have you checked those) and run the wires back for damage. Without having a wiring diagram near me (in Afghanistan) I don't have the foggiest idea where that particular ground is. If you can't get a copy of it, start at the switch and follow the wires back. Wish I could be of more help than that. Also try to use a voltmeter when you turn it on (this will help with the switch check). Understand I am not a great electrical person either, I just don't like to see no response threads. I always gotta try. Maybe be wrong, but like my father says you always have to try to help.
CJ
CJ
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Originally Posted by cpnhgnjnky
Basiclly, start at the switch(hey have you checked those) and run the wires back for damage. Without having a wiring diagram near me (in Afghanistan) I don't have the foggiest idea where that particular ground is. If you can't get a copy of it, start at the switch and follow the wires back. Wish I could be of more help than that. Also try to use a voltmeter when you turn it on (this will help with the switch check). Understand I am not a great electrical person either, I just don't like to see no response threads. I always gotta try. Maybe be wrong, but like my father says you always have to try to help.
CJ
CJ
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I grounded out the system with a new ground and there is no change. I can't figure this out for anything! I swear! It doesn't change in normal or max a/c, so it is getting airflow. Does anyone else have any other reasoning on why this might be happening? Help me!
-Matt
-Matt
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From: Mississauga,Ont.,Canada
I have had the same problem. If I have the blower motor for heat or ac on high my flasher will barely work when the vehicle is stop and will come back to life as I accelerate. I have tried cleaning the grounds,replacing the battery ground cable and added extra grounds but have yet to figure the problem. I am still working on it and will let you know if I solve the problem.
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