Hello FTE

I have a, you guessed it 91 e-150. The blower only goes on now when the fan is set to high. What would cause this? Is it easy to fix?

thanks

 

You sure it isnt an Aerostar?

Well it could be a bad blower resistor or a bad blower switch. I have found a lot of them with the switch and pigtail to the switch melted. But the resistor will allow the blower to run only on high often as well. Both are relatively simple fixes.

 

What is a pigtail?

 

Pigtail is the wiring connector to a device and its leads.

 

where would I locate the resistors on the van? Sounds easy enough.

 

It should be located in the blower housing in the engine compartment passenger side.

 

Specifically, looking at the blower enclosure, look just behind and a little lower than the blower motor. You'll see 4 wires going into the plastic blower housing. Everything is black there so you'll have to use a bright light. It has 2 bolt head screws holding it in place. You can pull it out without removing the connector. Just remove the 2 screws and pull it out and away enough to be able to look at the coils. They should be a flat silver color. They don't look like a resistor as in an electronic circuit. They are just those coils of 3 different sizes.

Only 1 coil needs to be bad to keep it from running on anything but high. When the fan speed is on low, it uses all 3 resistors. On Med Lo, it uses 2. On Med Hi it uses 1, and if it is that specific one resistor, that's what you will get.

While I would definitely check the resisitors, I would check the pigtail at the back of the fan speed control switch first. On my 89 Van, for some reason Ford spliced in a control panel marked "Thunderbird" and used barrel connectors to splice the wires. Just recently I had to replace those splices as all the insulation was melted.

Another problem could be the connector at the speed control switch (mine was partially melted) or the connector at the resistor pack.

 

Thanks, I am going to look at it soon. Where can I get these resistors? Radio Shack? or would Murrays or some other autoparts store be easier. anyone know the resistance (ohms) that each one is at?

 

Probably any auto parts store or Ford and you'll have to buy the assembly rather than a single resistor. They are not the normal resistors like Rat Shack carries. These are very high current and very low resistance.

As far as their resistance, they will be very, very low so unless you have a digital meter with a resolution of 0.1 ohms or smaller, they will probably read 0 ohms. (like a dead short)

All you are looking for is for one to be open. (Infinite resistance) So just put the meter across each of the 3 and look for either it to be open or nearly 0. Nearly 0 ohms is good in this case.

If in fact the resistor pack is bad, it should be visually obvious when you take it out and look at it. It would be likely that one of the coils (resistors) is broken.

Make sure you actually see a problem with the resistor pack before buying another one as it is more likely a bad connection at the resistor pack or the speed control switch.

 

Hello, so i finally got time to look at the blower, or should I say I tried to. My housing must be different then yours and the one described in my Hayes manual. It is this plastic (completely enclosed) box. I opened it up but there is just this little radiator looking thing inside. No sign of the resistor pack or the blower itself. Seems like ford thought the old way was to easy to get to. any ideas on where this stuff might be located on a 91 e-150. Thanks...

 

Did you look under the hood or inside the van? Your blower should be visible under the hood on that side.

 

I looked inside the van, on the passenger side under the dash. I believe the AC unit is blocking that area under the hood.

 

I believe that even with ac you should be able to get to it from the engine side. Been a while since I did a 91 but I do believe this is right.

 

Does yours have a battery on the passenger side? Look right behind the battery down low. Also have seen them located on the engine side of the blower plenum, almost in the tunnel.

 

Think I know where it is now, I see a thing with a wire harness going into a black box. Two screws... I will check it out.