I need some help . I have a 68 fury factory a/c car. Last week I turned on the defrost mode and nothing/ heat.. Nothing . No fan operation on any speed . Turned on the a/c and it all seemed to work fine . I put a fuse in and had the fan on hi and about 5 min later I smelled something burning which was the solder melting in the new fuse . I turned it off and looked things over and the fuse box had actually started to melt . I changed fan speeds while touching the fuse and it would get very hot on hi speed and I would turn it down or off before the fuse would blow . I also noticed the wires were warm out at the blower motor . So here's what I have done.... Replaced blower motor .. Pulled out the connectors at firewall . Cleaned/ dielectric grease on everything (it all looked good for the age..cleaned the blower motor ground. Put new ground cable on battery and ground to body. Took apart fan switch cleaned and sanded all contacts and confident it's all good . Pulled out blower resister it looked good.also ran blower on hi without the resister and fuse still getting hot . Also disconnected power wire from ignition switch to fuse box and ran a wire directly from battery to the fuse and tuned the fan on hi and it still got hot . I do have a sanden style compresser on the car and a powermaster alt. all this has been on the car for over a year and everything has worked perfectly . It also does this with the compresser unhooked and I checked the voltage at the fuse box and it was in the upper 13v range at fast speed upper 12s at an idle. So I welcome advice.. I am at a loss and just want to get it all working proper again
1968 fury..Need help.. Blower fuse blowing / fan speed HI setting
1 - 11 of 11 Posts
Joined
·
21,690 Posts
Welcome to Allpar. Was this a new, used or reman blower motor and is it the correct one for the car? Can you measure motor amperage draw on high? Is the blower fuse feeding the motor only and nothing else?
A high resistance will make lots of heat, as will excessive current and it will melt plastic. It sounds like up to the fuse is OK, but between the fuse and ground is the issue. A high resistance will actually lower current through a circuit, but the unintended heat from this will be a problem. The hottest point is probably where the circuit weakness is.
A high resistance will make lots of heat, as will excessive current and it will melt plastic. It sounds like up to the fuse is OK, but between the fuse and ground is the issue. A high resistance will actually lower current through a circuit, but the unintended heat from this will be a problem. The hottest point is probably where the circuit weakness is.
The original. Blower motor blew the fuse. I replaced it with a new one, the specs said meets or exceeds original equipment . Whatever that means. The blower fuse wiring feeds nothing else but is somehow tied in with the a/c circut from the factory.. the fan speed blows higher on the a/c setting (as i believe it is supposed to from the factory) and the blower fuse gets hottest while the a/c is on HI .Not sure I have the equipment to measure the amperage draw . What would I need and how would I.go about it ? Any other ideas or anything else I might check ?
Joined
·
21,690 Posts
Some multimeters have an Amps test setting. You would want to be sure that it could handle ~20 amps. A milliampere scale would be too small to read motor draw.
An nominal motor amperage free-running draw should be ~ 60% of the fuse size I would guess and may be stamped somewhere on the motor housing.
Without an ammeter, a voltage drop test on the meter's Volts scale between points may reveal where the trouble spot is. You would not want more than a volt drop between 2 points.
You could substitute a headlamp or other high-load component in the motor's place and see where the heat is. Are the fuse holder contacts clean and hold the fuse tightly?
Brass or copper terminals can tarnish and a 'pinch' with needlenose pliers might give you a firmer connection. Plated terminals can still corrode.
A nice 'scratch' as the terminals are pushed together can give a good low-resistance contact.
An nominal motor amperage free-running draw should be ~ 60% of the fuse size I would guess and may be stamped somewhere on the motor housing.
Without an ammeter, a voltage drop test on the meter's Volts scale between points may reveal where the trouble spot is. You would not want more than a volt drop between 2 points.
You could substitute a headlamp or other high-load component in the motor's place and see where the heat is. Are the fuse holder contacts clean and hold the fuse tightly?
Brass or copper terminals can tarnish and a 'pinch' with needlenose pliers might give you a firmer connection. Plated terminals can still corrode.
A nice 'scratch' as the terminals are pushed together can give a good low-resistance contact.
I had a 69 Fury. Nice to see some still around. Even though you have a "new" blower motor , it could have issues.Verify easy rotation of the blower wheel. I would wipe off the dielectric grease if the connections did not have it originally..Make sure connections at the motor and fuse box are clean. This won't solve your problem but check that you have the correct fuse in the circuit. Fuses should never get hot, they are designed to open up. You may have high resistance behind the fuse block. If you use an ammeter, make sure you connect it in series or inline not like your voltmeter which is parallel connected. These cars had a lot of problems with the voltage regulators. Might want to check as well.
Joined
·
32,304 Posts
+1
Joined
·
682 Posts
all else fails make sure the leads & connectors didn't get reversed somewhere during disassembly / cleaning.
yes we are talking about the same connector . Cleaned , all looks good . No wires reversed during cleaning, I had the problem before disassembly and cleaning . As much as I hate to...I think I am going to have to pull out the push button controls and check them out . I am running out of things to mess withchuzz said:
1 - 11 of 11 Posts
Join the discussion
Join now to ask and comment!