Repair Information On Your Imperial's Air Conditioning & Heater Fan/Blower

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Question from Mark (1963):

I've finally had enough of not having AC on the 'vert. I need to get to the fan motor. Do I need to pull the whole evaporator to get to the fan? If so (or not), how does it come out? Not very clear from the service manual.

Anyone "been there, done that" on a bug-eyed Imp?

Reply from Chris

It it not as difficult as you might imagine. But almost. And no A/C plumbing needs to be touched.

1. After removing (AND LABELING!) from the under-dash plenum all vacuum hoses, cables, and vacuum motor actuator rods (don't forget the recirculation door far above the trans hump), follow directions in shop manual for removing ground wire and connectors for blower motor.

2. Remove entire under dash duct housing. It is held in by only three screws as I recall.

3. Once removed, it is simple to swap out the blower motor.

4. Install as above, being sure to align the blower-to-firewall gasket and A/C duct hoses.

Should be the same basic process from 1959-1966.

Question from Kent (1965):

Would anyone know why my blower fan works fine on all three speeds for the A/C, but only on low and medium for the heater and defroster?

Reply from Dick:

The reason you didn't get an answer to this the last time you posted it is that the answer requires more information - specifically what type of AC you have.

While the ATC system wasn't in the literature for 1967, it was used on some late 67's. If you have that, the answer is that there are 5 speeds for the blower (not 3); the top two are only used for AC operation. The lower 3 speeds only are used for heat. I'm not sure about defrost, but your manual tells you all that if you have the service manual with the ATC info in it. If you don't have that portion of the manual, it is posted on the IML web site, either under 67 or 68 literature, perhaps both.

If you don't have ATC (automatic temperature control), your system should operate the way it is described in your manual. I don't have one for 67, so I can't quote from it to you. If there is a blower speed switch and no temperature dial, you have the older, simpler system.

Tell us which system you have, someone will be able to help you further. We'll also need to know what happens when you select the higher speed (no blower, or just the lower speed).

Follow-up from Kent:

No my car doesn't have ATC A/C just plain old standard A/C. Why three speeds on A/C and only two on heater and defrost mode? Sometimes there is a slight delay even with the high speed with A/C before it works. Any ideas.

Reply from Dick:

Probably, the high speed relay isn't getting it's drive signal in the heat/def position, but I need a wiring diagram to figure out for sure if this is normal or a malfunction.

For one thing, it may be normal for the high speed not to work in other than AC. That is the way the ATC control system works, for instance, as the super-duper blower speed isn't needed for heat/def.

Question from Jim (1966):

My '66 convertible is getting close to being finished mechanically, and I need a few miscellaneous parts. One of these is a blower motor for the heat/ac. I would prefer to buy one new, but the local auto place claims they aren't made anymore. Does anyone know if this part is available new and possibly what the part # is or what car uses the same part?

Reply from Chris:

You are in luck regarding the blower motor. According to the 300 Club, the exact same motor is used in '84
Peterbilt trucks.(!) It is a Fasco Heater Motor, #2807-516-039. It very likely was used in other years as well, and it should be easier to locate a 20 year old part than a 40 year old part.

Wiring connection is: black to black, red to brown, orange to green.

If that doesn't pan out, then a good used one is easy to find. They were used in Imperials from 1960-66 and senior Mopars from 1960-64. Thus there are plenty of potential donors.

Question from Jason (1967):

I am in need of a new resistor for my a/c heater blower motor. I have non atc. If anyone has an updated part number that would be great. The number on the part is 2607435. I would imagine that there is an updated part number but maybe not.


From Dick:

I can't help you on the blower resistor, but of course it is a simple wire wound resistor, so if you can match the value and wattage, you can substitute another resistor. If you need to know the electrical parameters, I can probably measure it for you.

By the way, the more common failure is in the blower speed switch which is in series with the resistor, not the resistor itself. These switches are still available at NAPA (you have to exchange the lever and mounting parts, but the new ones are identical electrically). SO --- make sure it is really the resistor that is bad before you go to an awful lot of trouble and still not fix it! I wrote up a detailed rebuilding procedure for these switches about a year ago, with the NAPA part number I used.

From Arran:

In your asking for a part number I would gather that this resistor has no markings on it indicating it's resistance value, correct? What I would do is find out the resistance and wattage of the old resistor and procure an EMA standard replacement of the same size from a TV shop or a electronic parts store. Can anyone dig out their ohm meter and measure this resistor?

Question from Tim (1967):

My '67's A/C blower motor never produced more than a mild breeze the whole time I've owned the car, and now it has finally died altogether. Good riddance! Is there a difference among replacement motors? Since I've never had a healthy one, I don't really know what to expect, but I'd pay extra for one that could really blow my hair back! Should I look for a NOS motor, or would a recently-made one likely be more powerful?


From John:

If your car has Autotemp, It may be something other then the motor that is bad. The system decides what speed the blower will operate at.

From Mike:

You should be able to diagnose this one pretty easily. As your car does not have auto temp (As far as I recall, having ridden in the fine auto!) it should be easy. I would first try to jump 12 volts right to the motor to see if you can get it to really blow. If yes, the problem is in the controls. If not, then you need either a) a rebuild or b) a new motor. I couldn't tell you what motors would interchange, but I'd lay money that any Chrysler blower motor from that era would work, if not perfectly, with some minor modifications.

Question from Don (1967):

My A/C blower motor runs at a very slow speed only. How do I get it to go to a faster speed? Oh and yes, I've tried the blower switch-changing to a faster speed does not increase the blower speed! Thoughts anyone?


From George:

Check the power leads going to the blower to see if there is current going to the high side of the blower motor. Another possible problem may be the lacl of or hardened lubrication on the motor bearings causing the motor to bind.

From John:

If you have ATC & the blower doesn't work, it could be related to that.

From Matt:

I would say it is the switch . That is what the problem was on my '66. YOu can have yours redone or there are vendors in Hemmings for these.

Question from Robert (1968):

I have a question about the heater and air conditioner fan. How do you get the fan motor to work? There is no fan speed switch and I have pushed in on all the buttons on the heater control panel and nothing. I have not fired up the engine yet that will come when I get the radiator back in and the exhaust hooked up. I am trying to make hangers for the tail pipe since I can not get them new. 

Reply from Dick:

If the car has ATC, it requires engine vacuum to energize the system. If you want to bypass that function, locate the "master switch", a vacuum operated device near the center of the air plenum, just about under the right side edge of the radio. There will be two vacuum lines and two electrical wires on it. It is color coded, you need to verify which one is the "master" switch by looking in your FSM. I think the master switch is either the yellow one or the green one. Which ever one it is, bypass it by connecting directly between the two electrical wires (a paper clip will do). This should make your system think it has vacuum, and your blower will come on. Nothing else in the system will work, however, since vacuum powers all the air control flaps and water valve, and enables the AC compressor.

You'll probably be more able to enjoy the car when you have an engine that runs.

Follow-up from John:

The green one is the blower switch, the yellowish-orange one runs the compressor.

Question from Jerry (1970):

I have a 1970 Imperial with Automatic Climate Control. Here is the problem. The heater motor does not respond properly. If I activate the defrost, it appears to work. When I switch to auto heat / cold the heater motor will run at high speed. The AC works for several minutes and then quits. If I go back to defrost, wait for the motor to start again, I can than go back to AC for a short time. If I jumper the motor, all functions appear to be working. A test light indicates that the motor in not getting any power. The manual states the resister block might be bad. I cannot find this part. Any ideas? If I find it, how do I test it.

Reply from John:

I'm pretty certain that the resistor is the same on the '70 as the '69. Is up a ways under the dash at about center, If it is bad, the coils will probably be burned & melted. Another possible culprit is a vacuum leak.

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