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AC 1340 Code


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Can someone look in their 99 FSM and see where the TEMPERATURE actuator is located on a 99 SEVILLE? This member is getting a 1340 code, something is going on with the actuator.

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1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

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I would try this (several times if necessary) before taking the car apart:

Key on slowly rotate temperature selection knobs from 60 degrees to 90 degrees and back to 60 degrees again. Did I mention slowly?

This might give the temperature controller and the temperature actuator an opportunity to synchronize themselves on the same page.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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I would try this (several times if necessary) before taking the car apart:

Key on slowly rotate temperature selection knobs from 60 degrees to 90 degrees and back to 60 degrees again. Did I mention slowly?

This might give the temperature controller and the temperature actuator an opportunity to synchronize themselves on the same page.

I wish I would have heard this before I changed mine, :lol: I took mine apart, there was a motor and two gears, if I recall the lube was dried up

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I drove the car a few miles to warm it up, several times I cycled through the passenger and driver side controls warm to cold very slowly. I noticed it would change cycle at around 69-70 degrees and blow out different vents. On 90 degrees under acceleration only the passenger side would blow warm, when the car would sit it would go back to blowing out cool air on both sides.

Thoughts?

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I drove the car a few miles to warm it up, several times I cycled through the passenger and driver side controls warm to cold very slowly. I noticed it would change cycle at around 69-70 degrees and blow out different vents. On 90 degrees under acceleration only the passenger side would blow warm, when the car would sit it would go back to blowing out cool air on both sides.

Thoughts?

When the car sits at IDLE?, the passenger side returns to blowing cold?

It sounds like the driver side stays cold all the time?

You have two actuators, a driver and a passenger actuator.

Check your coolant level and you might consider flushing your heater core also.

It sounds like you have a vacuum leak. Do you know if the parking brake on the 99 is released by vacuum or electrically? If it is released by a vacuum servo try setting your parking brake and release it by putting the car in R or D, does it release quickly?

If you take the kick/sound pad off the bottom of the dash on the passenger side, the ACM controller is there, it has a bunch of colors on it, look at my post #1 in this thread there is a photo of it. Remove the hose pack from that controller and RESET the hoses tightly, my system was losing vacuum at that location.

We still need to find your actuators, Ill check my manual later, I am sure it shows their location in the SEVILLE section. I think your driver side actuator is not functioning, if you knew where it was, you could watch them as you varied the temps..

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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.... I noticed it would change cycle at around 69-70 degrees and blow out different vents.
That would be normal if you have the system in AUTO mode (the top left button toggled).

I suggest you use the <MODE> switch and slowly cycle through all the air flow options several times and see what happens.

On 90 degrees under acceleration only the passenger side would blow warm, when the car would sit it would go back to blowing out cool air on both sides.
Could that be vibration related? And is the coolant reservoir at the proper level?

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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I drove the car a few miles to warm it up, several times I cycled through the passenger and driver side controls warm to cold very slowly. I noticed it would change cycle at around 69-70 degrees and blow out different vents. On 90 degrees under acceleration only the passenger side would blow warm, when the car would sit it would go back to blowing out cool air on both sides.

Thoughts?

When the car sits at IDLE?, the passenger side returns to blowing cold?

It sounds like the driver side stays cold all the time?

You have two actuators, a driver and a passenger actuator.

Check your coolant level and you might consider flushing your heater core also.

It sounds like you have a vacuum leak. Do you know if the parking brake on the 99 is released by vacuum or electrically? If it is released by a vacuum servo try setting your parking brake and release it by putting the car in R or D, does it release quickly?

If you take the kick/sound pad off the bottom of the dash on the driver side, the ACM controller is there, it has a bunch of colors on it, look at my post #1 in this thread there is a photo of it. Remove the hose pack from that controller and RESET the hoses tightly, my system was losing vacuum at that location.

We still need to find your actuators, Ill check my manual later, I am sure it shows their location in the SEVILLE section. I think your driver side actuator is not functioning, if you knew where it was, you could watch them as you varied the temps..

Yes, at idle the passenger side cools off, I will top of with coolant. I bought this car about a month a go so I am still learning things about it. I'll report back after I fill the coolant, that's if it needs it.

My Dad worked for Fisher Body his entire life and when it merged into CPC he retired. We both love our Cadillacs, he has the new Deville, probably his 20th Caddy and this would be my 6th. Thanks for your help.

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We are glad to be of help to fellow Cadillac Lovers!

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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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.

This leads me to think that there is air in the system. Does the purge line flow coolant?

On 90 degrees under acceleration only the passenger side would blow warm

This leads me to think that there is sediment (coolant tabs?) in the lower half of the heater core. Have you tried flushing it?

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I topped of the coolant and it was low about 1/2 gallon. Still no heat.

The radiator in this car looks pretty new, purge line flows just fine.

I found the actuators, they look different then the Devilles. You could see the drivers side in the picture I posted.

Question, how far is the actuator door suppose to swing to be functional for driver side dual controls?

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  • 2 weeks later...

I found that the passenger side actuator is not working at all, I think that is the cause of my issues.

I have a used parts guy that will get me both actuators pretty cheap, my problem is removing the passenger side actuator on my 99 STS, how do you get to that one last screw in the back. Do you take the dash cover off?

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