Heater fan speed problem

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robbragiel
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Heater fan speed problem

Post by robbragiel »

Heres the issue I got with my heater and i'm hoping someone on here might know what the problem might be before I start spending money.

Its on my 73 F250 cc, when I put the fan speed control in low or low/medium the fan will work just fine. But when I put the fan speed control in medium/high or high the fan will run for about a minute and then it shuts off then I have to turn the heater off and wait about an hour then I can turn it back on to low or low/medium. It sounds like something is getting to hot thats why its shutting itself off. Can it be the heater control relay right under the dash or could it have something to do with the blower motor. I sure dont feel like pulling all that crap out but if I have to then I will. Just hoping maybe someone on here might have had this kind of problem before.

Last edited by robbragiel on Sun Dec 05, 2010 9:30 am, edited 1 time in total.

73 F250 CC Shortbed
73 F350 Chassis Cab CC Longbed
02 F350 4x4 CC Longbed Diesel
02 Excursion 4x4 Diesel
08 Fusion (daughters)
13 Focus (sons)
13 Fusion Hybrid
All of them are registered and get driven regularly


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InfoFord
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Re: Heater fan speed problem

Post by InfoFord »

what size circuit breaker you running on the heater circuit plus make sure your heater switch and contacts are in good shape


robbragiel
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Re: Heater fan speed problem

Post by robbragiel »

I'll have to ck and see what size the fuse is but I believe its the stock size fuze. Either a 20 or 30 amp fuze. I did check all the conections that I could get too and found nothing loose or disconnected.

73 F250 CC Shortbed
73 F350 Chassis Cab CC Longbed
02 F350 4x4 CC Longbed Diesel
02 Excursion 4x4 Diesel
08 Fusion (daughters)
13 Focus (sons)
13 Fusion Hybrid
All of them are registered and get driven regularly


jrzoffroad
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Re: Heater fan speed problem

Post by jrzoffroad »

Sounds like a fan motor switch. On low and medium speeds it goes through the resistor and on high it bypasses the resistor thus giving you full fan speed.


robbragiel
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Re: Heater fan speed problem

Post by robbragiel »

jrzoffroad wrote:

Sounds like a fan motor switch. On low and medium speeds it goes through the resistor and on high it bypasses the resistor thus giving you full fan speed.

Is that the switch next to the heater controls or is it somewhere under the dash?

73 F250 CC Shortbed
73 F350 Chassis Cab CC Longbed
02 F350 4x4 CC Longbed Diesel
02 Excursion 4x4 Diesel
08 Fusion (daughters)
13 Focus (sons)
13 Fusion Hybrid
All of them are registered and get driven regularly


jrzoffroad
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Re: Heater fan speed problem

Post by jrzoffroad »

It is the vertical fan speed switch on the HVAC controls on the dash.


robbragiel
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Re: Heater fan speed problem

Post by robbragiel »

jrzoffroad wrote:

It is the vertical fan speed switch on the HVAC controls on the dash.

Thanks, I'll have to swap that out and see if it works

73 F250 CC Shortbed
73 F350 Chassis Cab CC Longbed
02 F350 4x4 CC Longbed Diesel
02 Excursion 4x4 Diesel
08 Fusion (daughters)
13 Focus (sons)
13 Fusion Hybrid
All of them are registered and get driven regularly


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