After a few years of working at Haldeman Ford and almost a decade now of wrenching on cars by myself, I've come to realize a few things, one of which, is car enthusiasts. As 80% of them about longtubes, intakes, or cams, and they can tell you what they've had, what they want, how to install them, how they work, and what kind of gains you're going to get from them. But ask them something about the heating system, and they're lost. I'll go over some basic heating system issues, but if you use your common sense, you can diagnose anything properly. And DIAGNOSE is the key word here; any parts-changing Jiffy Lube monkey can just chuck parts at a car until the problem is gone, it takes a real technician to diagnose the car and fix it right the first time.
So it's the middle of winter and you have no heat. Instead of jumping on the local forum and begging for the cheap, easy answer, think about it. Is anything coming out the vents?
Yes - you have a base heating system issue.
No - you have an electrical heating system issue.
For now, I'm only going to cover the "No" answer.
So nothing is coming out the vents. The first thing to do would be to put your hands up by the windshield. Is anything coming out the defroster vents?
Change the settings for output. Is it always on defrost no matter where you put it? If it is, you most likely have a vacuum issue. That position switch operates on vacuum (depending on which setting you select, it directs that vacuum to a series of doors inside the climate control system that direct the cool or hot air to the vents, floor, defroster, etc.) and when you have a loss of vacuum going to the switch it defaults to the safety setting - DEFROSTER. Trust me, if it's the middle of winter and you can only have air going in one direction, you want it on the windshield.
Does the air come out the incorrect or only on some but not the other settings (not defrost)? Sorry, you're going to have to pull the dash and inspect those doors and vacuum actuators I was talking about, sounds like one of them is stuck or broken.
So let's say that's not your issue, nothing comes out anywhere, even on the defrost. Change the speed settings. Does it work on high? If it only works on the high setting, congratulations, you're looking at needing a blower motor resistor. 12V is sent to the blower motor, but it must first go through the blower motor resistor. For the middle and lowest setting, that 12V goes through a resistance and is obviously less on the other side, resulting in less power to the blower and therefore less output speed. When you put it in the high setting, it bypasses the resistor and sends the motor all it can.
Well let's say it doesn't work on any speed setting. Why is this, you think to yourself? Maybe the blower motor isn't getting any juice. Confirm this by accessing the blower motor. Go under the passenger side dash, remove the three screws holding it in, and drop it down. Put the controls on Floor and High. Key in the on position (cluster lights up). Put a test light backprobing the orange and blue wires going into the blower motor. If your diagnosis is correct so far, the test light should not light up. Go under the driver side and remove the fusebox cover. Check and inspect all fuses, especially the 30A. If this is popped, there's your problem. If you have power at both sides of that fuse, you need to get your hands on the ford electrical manual and continue diagnosing. Trace the wire by hand and find the open.
Well let's say it's not an electrical issue. When you backprobed those two wires, you had power and ground and the test light lit up. So if the blower motor is getting voltage and not operating, it's because it's done for. Is this unusual? Nope. Other than window motors and regulators, blower motors are one of the most common things seen on Fords for a long time. You're usually going to get 100,000+ miles out of one, but then again there are the freaks that don't even get out of the warranty period. Like any electrical motor, they take a dump all of a sudden and usually without warning.
This is what happened on the wife's car. So, how to replace a blower motor on a 98 Cobra? (If memory serves me correctly, this EXACT procedure is good on any Mustang 94-04, and very similar steps are used on pretty much all fords 94-present.)
You will need the following tools, but you can improvise if you do not have any of these:
1. Big Fing Hammer - you actually need a really small one, but I like to use battleships to sink rowboats
2. Dikes - diagonal cutters
3. Butterfly wire strippers - a universal cutter/crimp/stripper tool will work too
4. 5/16" drift
5. Wire crimper
6. 8mm socket and ratchet
7. test light
8. "general pliers"
9. 2x 14AUG wire crimps
1. Look up under the passenger side of the dash and you will see this:
2. Remove the three 8mm screws (yes, they are body screws) and the black metal retaining bracket from the blower motor case
3. Remove the electrical connector tabs from the case and allow the motor to drop down
4. Carefully cut the two wires going into the blower motor close to the blower motor...leave yourself as much wire attached to the car as possible
5. Bring the blower motor inside where it is not freezing cold
6. Take off the black plastic blower motor case. Remove the metal retaining nut on the blower motor wheel (birdcage) with the dikes you used to cut the electrical wires. A new nut should be provided with your new blower motor.
7. Hold the birdcage with your thighs or your ankles (not holding the motor, hold the cage) and use the hammer and drift to knock the center pin out of the cage (this center pin is attached to the motor, so the motor and pin is removed). I recommend holding it with your body like this because trying to pin it between something and the floor or in a bench mounted vice can be very unforgiving to the plastic birdcage.
8. Ta-da!
9. This is what comes in your new blower motor package (not the plastic case to the left, that is part of the car).
10. You will need to attach the provided weatherstripping seal. Whatever Korean geniuses that Autozone buys from were so smart that they cut the shape of the seal to match the outside of the blower motor, but it needs to go on the inside. If you have the same issue, trim as necessary, just make sure you get a circular seal going around the outside.
11. Install the birdcage
12. Use your "general pliers" to install the new retaining nut on the bird cage. be gentle.
Installation is the reverse of removal. Remember those two wires? The ones on this one were orange and black. Orange goes to orange on the car. Black goes to blue on the car. Cut the wires on the blower motor to about 1" longer than the wires are on your old one - this will give you some more room to work under the dash and enough wire to make a mistake or two. Strip about 1/4 inch of wire off each end on the car and on the blower motor, and install the crimps on to the blower motor. Get back into the car and crimp the car side of the wires.
A note when reinstalling the blower motor: after your wires are hooked up, align the blower motor and hold it in place while you try and put up the soft plastic case. Trying to install both at the same time can be a pain. Make sure you get all three screws started by hand before tightening any of them. Tighten until snug, no need to be Hercules. Make sure the wires do not get pinched between the blower motor and the blower motor housing.
Enjoy, it should take you about 30 minutes working slowly and CAREFULLY with attention to detail or less if you are experienced. Take your time and do it right the first time, and make sure you've started from the beginning and done your diagnosis correct. I've seen quite a few "technicians" embarrassed because they put in a blower motor only to have it not fix the problem and later find a loose connection or a simple blown fuse. If it's your $69.88+ tax that you spent on a blower motor, you're going to be a little more than embarrassed if you threw the part at the problem and it turns out to be something simple.
So it's the middle of winter and you have no heat. Instead of jumping on the local forum and begging for the cheap, easy answer, think about it. Is anything coming out the vents?
Yes - you have a base heating system issue.
No - you have an electrical heating system issue.
For now, I'm only going to cover the "No" answer.
So nothing is coming out the vents. The first thing to do would be to put your hands up by the windshield. Is anything coming out the defroster vents?
Change the settings for output. Is it always on defrost no matter where you put it? If it is, you most likely have a vacuum issue. That position switch operates on vacuum (depending on which setting you select, it directs that vacuum to a series of doors inside the climate control system that direct the cool or hot air to the vents, floor, defroster, etc.) and when you have a loss of vacuum going to the switch it defaults to the safety setting - DEFROSTER. Trust me, if it's the middle of winter and you can only have air going in one direction, you want it on the windshield.
Does the air come out the incorrect or only on some but not the other settings (not defrost)? Sorry, you're going to have to pull the dash and inspect those doors and vacuum actuators I was talking about, sounds like one of them is stuck or broken.
So let's say that's not your issue, nothing comes out anywhere, even on the defrost. Change the speed settings. Does it work on high? If it only works on the high setting, congratulations, you're looking at needing a blower motor resistor. 12V is sent to the blower motor, but it must first go through the blower motor resistor. For the middle and lowest setting, that 12V goes through a resistance and is obviously less on the other side, resulting in less power to the blower and therefore less output speed. When you put it in the high setting, it bypasses the resistor and sends the motor all it can.
Well let's say it doesn't work on any speed setting. Why is this, you think to yourself? Maybe the blower motor isn't getting any juice. Confirm this by accessing the blower motor. Go under the passenger side dash, remove the three screws holding it in, and drop it down. Put the controls on Floor and High. Key in the on position (cluster lights up). Put a test light backprobing the orange and blue wires going into the blower motor. If your diagnosis is correct so far, the test light should not light up. Go under the driver side and remove the fusebox cover. Check and inspect all fuses, especially the 30A. If this is popped, there's your problem. If you have power at both sides of that fuse, you need to get your hands on the ford electrical manual and continue diagnosing. Trace the wire by hand and find the open.
Well let's say it's not an electrical issue. When you backprobed those two wires, you had power and ground and the test light lit up. So if the blower motor is getting voltage and not operating, it's because it's done for. Is this unusual? Nope. Other than window motors and regulators, blower motors are one of the most common things seen on Fords for a long time. You're usually going to get 100,000+ miles out of one, but then again there are the freaks that don't even get out of the warranty period. Like any electrical motor, they take a dump all of a sudden and usually without warning.
This is what happened on the wife's car. So, how to replace a blower motor on a 98 Cobra? (If memory serves me correctly, this EXACT procedure is good on any Mustang 94-04, and very similar steps are used on pretty much all fords 94-present.)
You will need the following tools, but you can improvise if you do not have any of these:
1. Big Fing Hammer - you actually need a really small one, but I like to use battleships to sink rowboats
2. Dikes - diagonal cutters
3. Butterfly wire strippers - a universal cutter/crimp/stripper tool will work too
4. 5/16" drift
5. Wire crimper
6. 8mm socket and ratchet
7. test light
8. "general pliers"
9. 2x 14AUG wire crimps
1. Look up under the passenger side of the dash and you will see this:
2. Remove the three 8mm screws (yes, they are body screws) and the black metal retaining bracket from the blower motor case
3. Remove the electrical connector tabs from the case and allow the motor to drop down
4. Carefully cut the two wires going into the blower motor close to the blower motor...leave yourself as much wire attached to the car as possible
5. Bring the blower motor inside where it is not freezing cold
6. Take off the black plastic blower motor case. Remove the metal retaining nut on the blower motor wheel (birdcage) with the dikes you used to cut the electrical wires. A new nut should be provided with your new blower motor.
7. Hold the birdcage with your thighs or your ankles (not holding the motor, hold the cage) and use the hammer and drift to knock the center pin out of the cage (this center pin is attached to the motor, so the motor and pin is removed). I recommend holding it with your body like this because trying to pin it between something and the floor or in a bench mounted vice can be very unforgiving to the plastic birdcage.
8. Ta-da!
9. This is what comes in your new blower motor package (not the plastic case to the left, that is part of the car).
10. You will need to attach the provided weatherstripping seal. Whatever Korean geniuses that Autozone buys from were so smart that they cut the shape of the seal to match the outside of the blower motor, but it needs to go on the inside. If you have the same issue, trim as necessary, just make sure you get a circular seal going around the outside.
11. Install the birdcage
12. Use your "general pliers" to install the new retaining nut on the bird cage. be gentle.
Installation is the reverse of removal. Remember those two wires? The ones on this one were orange and black. Orange goes to orange on the car. Black goes to blue on the car. Cut the wires on the blower motor to about 1" longer than the wires are on your old one - this will give you some more room to work under the dash and enough wire to make a mistake or two. Strip about 1/4 inch of wire off each end on the car and on the blower motor, and install the crimps on to the blower motor. Get back into the car and crimp the car side of the wires.
A note when reinstalling the blower motor: after your wires are hooked up, align the blower motor and hold it in place while you try and put up the soft plastic case. Trying to install both at the same time can be a pain. Make sure you get all three screws started by hand before tightening any of them. Tighten until snug, no need to be Hercules. Make sure the wires do not get pinched between the blower motor and the blower motor housing.
Enjoy, it should take you about 30 minutes working slowly and CAREFULLY with attention to detail or less if you are experienced. Take your time and do it right the first time, and make sure you've started from the beginning and done your diagnosis correct. I've seen quite a few "technicians" embarrassed because they put in a blower motor only to have it not fix the problem and later find a loose connection or a simple blown fuse. If it's your $69.88+ tax that you spent on a blower motor, you're going to be a little more than embarrassed if you threw the part at the problem and it turns out to be something simple.
