AC 1340 Code

[BodybyFisher]

On the way to Pennsylvania last week my AC started blowing warm. I had just had the carriage down, and I was worried that I disturbed a line. I assumed that it needed a charge, so I got an evacuate and recharge, it made no difference, even though it was over a pound low. I left my manual home so I didnt know what an AC 1340 was until I logged on at night. The Aix Mix Door. Kevin explains it here http://caddyinfo.ipbhost.com/index.php?sho...446&hl=1340 This actuator is what moves the air mix door between the heater core and the evaporator as you raise or lower the temperature control.

After reading that thread I bought a new actuator the next day. I got the glove compartment out, the screws were too hard to get to. I only had metric sockets with me and the screws were SAE. So I disconnected the rod discovered that if I move the door one way I got AC and if I pushed it the otherway I got heat. I jammed the door at the full AC extreme for the remainder of the trip.

Tonight, I removed the top cover, glove compartment and air bag (be careful with the air bag, there is a disable/removal procedure in the manual, watch out for static electricity and face it away from you

Here is the old actuator in place with the rod disconnect on one end

I think I had a leak at this location, the connection was loose and this would explain why I lost my AC going up hills

I used some RTV to seal the connection, I took the car out and under hard acceleration the AC stayed steady, so maybe I fixed the vacuum leak

I also reset all of the connections here

Here is the old actuator

Now I know why foam is blowing out of the vents once in a while, the foam the is around the outlet air volume valve in each outlet vent is deteriorated, see photo, the vent on the right lost its foam and the foam on the door on the left is fragile.

Once I replaced the actuator I had cold air again, the old actuator must have been defective. I took it apart and the gears looked good, but maybe the motor was bad, it smelled like It was burning

[Bruce Nunnally]

Good repair, and very nicely documented. Good job all around.

[Cadillac Jim]

This post would be an excellent addition to the DIY blog. I'm figuring that I may be doing this repair sometime in the next couple of years and would want to find this post. The tip on the Styrofoam on the vent doors is excellent; I will try to have new vent doors as well as an actuator.

[KevinW]

It is possible to remove and replace the actuator, after removal of the glove-box liner, using a 1/4" drive ratchet wrench (and 5.5 mm socket?). Here's a photo of the internal mechanism. I was able to revive two inoperative actuators by removing the motor (pull upwards and disconnect the electrical leads), then tapping the metal housing lightly in various orientations; test with a 9 volt battery before and after. One could speculate that these cars ride too smoothly, allowing the build-up of brush material in the 'wrong' areas after 10+ years!

[BodybyFisher]

It is possible to remove and replace the actuator, after removal of the glove-box liner, using a 1/4" drive ratchet wrench (and 5.5 mm socket?). Here's a photo of the internal mechanism. I was able to revive two inoperative actuators by removing the motor (pull upwards and disconnect the electrical leads), then tapping the metal housing lightly in various orientations; test with a 9 volt battery before and after. One could speculate that these cars ride too smoothly, allowing the build-up of brush material in the 'wrong' areas after 10+ years!

Yes, now that I had it out, I can see that with the correct tools which I did not have at the time it is possible. However I thought it was held in place with three screws, not 2 as it was. The third one would be near the heater core side, and its near impossible to get to, but that screw was not used on mine. Thanks

[JimD]

....I was able to revive two inoperative actuators by removing the motor (pull upwards and disconnect the electrical leads), then tapping the metal housing lightly in various orientations; test with a 9 volt battery before and after. One could speculate that these cars ride too smoothly, allowing the build-up of brush material in the 'wrong' areas after 10+ years!

I would bet serious money that most, if not all, "failed" actuators, position sensors, etc could be repaired if the person doing the job was capable and willing to do the job rather than replace the part and move the car out of the bay.

Probably not going to happen very often at a dealership operation. The economics for the tech doing the work does not work.

In the case of DC motor applications like the HVAC door actuator in this example, the motor brushes can wear or become stuck in the brush holders, the bushing lubricant can dry out, or some other simple little easily corrected item can fail. A capable DIY person can take the time to identify and correct the real problem; the tech at the dealership cannot afford to get into the details.

Replace the part and move on to the next job.

[BodybyFisher]

....I was able to revive two inoperative actuators by removing the motor (pull upwards and disconnect the electrical leads), then tapping the metal housing lightly in various orientations; test with a 9 volt battery before and after. One could speculate that these cars ride too smoothly, allowing the build-up of brush material in the 'wrong' areas after 10+ years!

I would bet serious money that most, if not all, "failed" actuators, position sensors, etc could be repaired if the person doing the job was capable and willing to do the job rather than replace the part and move the car out of the bay.

Probably not going to happen very often at a dealership operation. The economics for the tech doing the work does not work.

In the case of DC motor applications like the HVAC door actuator in this example, the motor brushes can wear or become stuck in the brush holders, the bushing lubricant can dry out, or some other simple little easily corrected item can fail. A capable DIY person can take the time to identify and correct the real problem; the tech at the dealership cannot afford to get into the details.

Replace the part and move on to the next job.

When I was a kid I used to fix parts such as this, I still do, as an example, I have fixed my Key Fob a bunch of times. But most of the time brushes are shot, bearings shot or parts are worn. I don't have time to do these jobs twice, like I did as a kid. I figure that the cash I save diagnosing and repairing the problem myself, can be put into replacing worn parts, in the long run I end up with a better overall experience behind the wheel. And I learn something.

[Logan]

I think the foam is natural issue. 2 Cadillacs now.. where as the car gets older...more foam chunks show up on me and the floor.

[rek]

About that foam.....I used silicone fuel line (Hobby Store) to seal all the vents, in my 96 Eldo. I inserted a piece of bare welding rod (aluminum) in the fuel line, to hold it straight. Then I sliced it with an x-acto blade, length-wise. Cut the ends at a 45 (mitre joint like). Press the line (4 pieces/each vent) on the leading edge of the back side of the vents. It seals well. I did remove all the OEM foam. It had been installed with no rhyme or reason in that it was here and there, not really sealing anything, AND partially interupting the air flow.

No more foam chunks blowing out........AND most, if not all, the "Conditioned" air comes through the vents, rather than being wasted inside the dash..........

[cdv70]

Tonight, I removed the top cover, glove compartment and air bag (be careful with the air bag, there is a disable/removal procedure in the manual, watch out for static electricity and face it away from you

What has to be done to remove the air bag safely ?

[BodybyFisher]

Disconnect the battery, pull the fuse, disconnect the yellow connector, face it away from you at all times and watch out for static electricity. I don't have my manual handy to post the exact procedure, but that is basically it.

[heymantim]

I noticed today when I was driving, that when I accelerated the air in the vents would almost completely stop, then when I started to coast, or not accelerating fast, the air returned. Does this sound like the same problem? I have a 1997 concours (deville).

[Ranger]

I noticed today when I was driving, that when I accelerated the air in the vents would almost completely stop, then when I started to coast, or not accelerating fast, the air returned. Does this sound like the same problem? I have a 1997 concours (deville).

Sounds like a vacuum leak. When you accelerate, engine vacuum drops and the system defaults to defrost. When you decelerate, engine vacuum builds and the system returns to where it was set (vents).

[BodybyFisher]

I had the same problem and I replaced the nylon tubing to the tank, the check valve, the vacuum tubing (rubber) and it didnt fix the problem. It was not until I removed and reset the colored vacuum hoses on the programmer and main hose that it was fixed. Try resetting the vacuum hoses under the dash after you check the hoses, tubing and check valve under the hood. A hand held vacuum pump with a gage on it is helpful when you diagnose this. Sears sells a good one.

[BodybyFisher]

I just realized that I might have made an error when I did my repair above. I used RTV. I think but I am not sure, that RTV is not O2 sensor safe. Is that true?

[WarrenJ]

RTV probably vulcanizes in less time than it took you to reassemble your dash; It's inert thereafter.

Assuming there were any O₂ sensor-harmful malefactors present initially, they were likely long gone before you cranked the N*.

Regards,

Warren

[BodybyFisher]

RTV probably vulcanizes in less time than it took you to reassemble your dash; It's inert thereafter.

Assuming there were any O₂ sensor-harmful malefactors present initially, they were likely long gone before you cranked the N*.

Regards,

Warren

That's great Warran thanks, I was thinking that pieces could be sucked into the intake system.

[iametarq]

Great post and pictures! I also have the codes 1340 & 1344 for actuators on both sides, but I have never not had a problem with my actual air flow?? I still have not gotten into them. I seem to recall the new actuators being more than $100 for each of them.

[BodybyFisher]

Great post and pictures! I also have the codes 1340 & 1344 for actuators on both sides, but I have never not had a problem with my actual air flow?? I still have not gotten into them. I seem to recall the new actuators being more than $100 for each of them.

Yes James, they are not cheap. You might be able to buy them at a scrap yard, why not? I recall that I paid $142 for mine directly from the dealer in Virginia Beach. You might find better prices at Brasington - gmotors.com

[davidkriegel]

Thank you for the superb helpful post. My 99 caddy also had this code and had no hot air on the drivers side. There is a small amount of heat on the passanger side but boy is it cold! Using your instructions I found that the valve motor located under the glove box WORKS FINE Therefore there must be another door and valve broken

The Caddy dealership wants $1000 to start work NOT YET? ANy ides out there to get to the other mystry motor so I can get some heat? Thanks

[BodybyFisher]

Thanks, I post these details so that they help someone, glad my experience helped.

I don't have independent driver and passenger heat controls, so I can't help you with each actuator's location. Maybe someone with a 99 can post a scan of the actuator's location. If you have separate drivers and passenger heating controls you have two actuators

Keep in mind that the symptoms you are having may be related to low coolant or air in your system.

You seem to be having reduced heat from both sides.. What code are you getting? 1340? There is a code for each actuator if I am not mistaken. Watch the actuator as you raise and lower the temp to make sure that it makes a full swing and that the door or motor is not binding. The motor has a few gears in it that can jam up and the motor can be intermittant. You may have more than one problem low coolant, a clogged heater core and a bad actuator. You might try flushing the heater core also. And make sure you are getting coolant from the air purge/bleed line at the coolant tank.

[Ranger]

I believe the actuators are one above the other. One is accessible through the removed glove box. The other is below it and accessible from below.

[KHE]

Thank you for the superb helpful post. My 99 caddy also had this code and had no hot air on the drivers side. There is a small amount of heat on the passanger side but boy is it cold! Using your instructions I found that the valve motor located under the glove box WORKS FINE Therefore there must be another door and valve broken

The Caddy dealership wants $1000 to start work NOT YET? ANy ides out there to get to the other mystry motor so I can get some heat? Thanks

The other actuator is behing the glove box on a dual zone system. Very easy to access/repair. This is at most a 30 minute job for an expierenced tech... it is disgusting how many dealers are downright thieves that ruin the reputation of good, honest dealers not to mention Cadillac/GM.

[Capt'n Rob]

My 99 STS has no heat but I do have air, when the the heat is on and I accelerate warm air does come out but very little. I have the B1340 error message and I thought for the heck of it I would pull my glove box out and investigate. My set up looks nothing like the Deville. Should I be looking for anything different? Where are the actuators and rods?

I also have codes C1710 and C1715.

Should I be looking under my dash cover? How is that removed? Any help on this would be great, cold weather is setting in here in Michigan and I will need my heat very soon.

I fixed many things thanks to this forum and I refuse taking it to the dealer if all possible.

Any help would be appreciated...... Thanks in advance and thanks for these great forums.

[BodybyFisher]

My 99 STS has no heat but I do have air, when the the heat is on and I accelerate warm air does come out but very little. I have the B1340 error message and I thought for the heck of it I would pull my glove box out and investigate. My set up looks nothing like the Deville. Should I be looking for anything different? Where are the actuators and rods?

I also have codes C1710 and C1715.

Should I be looking under my dash cover? How is that removed? Any help on this would be great, cold weather is setting in here in Michigan and I will need my heat very soon.

I fixed many things thanks to this forum and I refuse taking it to the dealer if all possible.

Any help would be appreciated...... Thanks in advance and thanks for these great forums.

If you have the 1340 code it is telling you that your HOT COLD actuator is not operating correctly, while its not the same as my Deville, you still have an actuator, you just need to find it. Someone here will help you that is familiar with its location on the 99