1977 Ford F-150 Accessory saftey relay

44TRACTORMAN

MEMBER
1977 FORD F-150
V8
4WD
AUTOMATIC
160,000 MILES

I have 77 ford f 150 and the a/c heat blower will not run, with a new accessory saftey relay installed. The old one got hot (for unknown reason) and melted a terminal out. I bought new one and installed it, three prongs and three plugs only one way to fit. Ok when this would not work I used a jumper wire to "cross two of the wires in place of the realy and it came on and seemed to work fine, however the jumper wire was getting a little hot and I dont want to burn up my truck, New fuses, new relay and out of ideas. Thanks

3 Replies

JACOBANDNICKOLAS

MECHANIC
108,320 POSTS

Is the switch good? Also, have you checked how many amps the motor is drawing? I question if the motor is bad (still runs) but caused the melt down. You may want to check the switch itself.

Let me know what you find.

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Tuesday, November 24th, 2009 AT 6:39 AM

44TRACTORMAN

MEMBER
1 POST

Checked amps on old fan after I removed it it was pulling 4.8 to 4.9 amps new one in same test mode pulled 2.3 2.5 I have not finished installing it yet to see if it will work correctly but old one looked melted in and around the windings. This problem is a pain in the butt to get to and remove to fix. Will let you know what else I find.

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Saturday, November 28th, 2009 AT 1:20 PM

JACOBANDNICKOLAS

MECHANIC
108,320 POSTS

Something tells me that is the problem. I know they are a pain. You should try replacing one on a newer F150. THe entire dash has to come out.

Let me know how it goes.

Joe

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Saturday, November 28th, 2009 AT 2:05 PM