Mechanics

OUT OF PATIENCE AND MONEY/HEATER

1998 Cadillac Catera

Heater problem
1998 Cadillac Catera 6 cyl Front Wheel Drive Automatic 104, 00 miles

Ok, was talked into buying this car for repair cost. Spent 3800. Now tech is saying heater does not work, he does'nt want to fix. Was told the dash has to come out. Is there a quick fix, the doors are not opening, blower works. I am unemployed, lost my Lexus, home and out of money. I really need some help here. Cant believe I bought this car. So much for trustong people who want to help.
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52xmax
December 11, 2009.



It is a dual zone system, I don't see where it defaults to full cold in the event of a failure, and I can't be sure that both actuators have failed. You have a few things to be concerned with. Is the lines to the heater core hot, indicating that there is hot water flowing through it. There is a hot water control valve that controls this, there is also an auxiliary heater water pump, description as follows; Auxiliary Water Pump Description
Two electric engine coolant pumps are used in conjunction with the belt driven mechanical pump.

The continuously running electric pump mounted on the RH strut tower assists the flow of warm coolant to the heater core at idle when the ambient temperatures are low. A failure in this pump would result in poor heating performance, especially at idle.

The second electrical pump is mounted on the LH of the radiator, which provides the additional flow of coolant through the radiator. This pump is energized when the coolant temperatures reach 90 °C (194 °F)

I would say if you don't have hot water to the core, the problem is not actuators. Check the vacuum line to the hot water valve, I don't find anything that says when it has vacuum, just when it blocks flow. With that it is either going to have a vacuum signal until max AC is selected, or it is not going to have a vacuum signal until max AC is selected. Here is it's description; • The Water Valve. The hot water valve shuts the entry of the heated coolant to the heater core when both the driver and the passenger temperature settings are requesting a maximum A/C. Thus, the cooling efficiency is increased.

A scan tool would be required to check for HVAC codes, as well as operating the actuators to see if they are moving. The dash does not need to come out for actuator replacement.

Factoryjack
Dec 11, 2009.
Wow, thanks for your quick response. I dont feel as fustrated now. Youre the first that has made any sense. The hoses do get hot when the car is running and the heater is on.
I really do appreciate your help. At least I have something to work with now and a little more knowledge. I will keep you posted, and have a Merry Christmas.

Tiny
52xmax
Dec 12, 2009.
I'm having a similar issue with my catera, I have very little (around 60 degrees) heat on the dirver side and ICE COLD air from passenger, i've looked EVERYWHERE for a manual for this car to locate a repair manual to check the actuators, cant buy one from chilton or haynes, neither produces one, keep us updated if you have any relief with your car, my funds are limited as well. Love the luxary but hate the repair cost

Tiny
Teggyboy411
Jan 10, 2010.
If you have low heat from both sides, it sounds more like a cooling system problem. One side could be slightly warmer just due to proximity to heater core and hvac case design. Check that the vehicle is getting up to operating temp, and that the heater valve and auxiliary water pump are working.

Factoryjack
Jan 10, 2010.
Its not low heat its warm heat about 65 degrees, and NO heat, I mean ice cold a/c air on the pass. Side.

Tiny
Teggyboy411
Jan 11, 2010.
I haven't had mine looked at yet, the Cadillac dealership wants $600. Just to look at. I have found someone else to look at it this week and will let you know what they say. I like this site, these guys sure help educate us girls. Of course I popped the hood to look at and closed it right back, but at least I can talk with some intelligence now.

Tiny
52xmax
Jan 11, 2010.
I can't say that you don't have actuator issues, the mechanical portion is something you may be able to rule out. Think of it this way, anytime your operating in 'auto' the A/C compressor is operating. If you have no hot water flowing through the heater core, you are basically operating the same as though you selected 60 deg on the panel. And the same rule applies, the closer outlet to the core is going to be colder. The physical aspect is something that you may be able to check yourself, like whether or not hot water is passing the valve. On a catera, it is not real easy to access this valve, or the inlet/outlet hoses to the core, but it can be done. To assume it is actuator problems is just that, an assumption. No manual will provide you a method for checking the actuators, It will require a scan toll that can read data, and possibly perform functions like actuator control.

Factoryjack
Jan 12, 2010.
Ive checked the hoses to the core, and they are getting hot, I dont know about the valve working, I have no idea where to look for the valve, nor the actuator doors. Dealership here told me that to hook it up and test the doors it would be $100, and when I asked about a repair manual helms is the only company ive found so far that makes one-$200, anyone else find a manual? Id really like to find a diagram for the doors to try to manually open them and see if that fixes it.

Tiny
Teggyboy411
Jan 12, 2010.
The valve is located at rear of engine, behind the intake, black/three hoses and vacuum line. I can tell you this, the manual is not going to give you a diagram of the doors. Here is the chart for improper delivery and temp, from GM service info.

Service Information
1998 Cadillac Catera | Catera (VIN V) Service Manual | HVAC | HVAC Systems - Automatic | Diagnostic Information and Procedures | Document ID: 283631

Air Delivery and Temperature Control Check
Improper Air Delivery Step
Action
Value(s)
Yes
No

1
Was the Air Delivery System Check performed?
--
Go to Step 2
Go to Air Delivery System Check

2
• Install the scan tool.

• Select the actuator tests from the Air Conditioning SPECIAL FUNCTIONS menu.

• Select one actuator test at a time and command the actuator from 0% to 100%.

• Monitor the air flow when commanding the selected actuator (e.G, good air flow should be felt when the floor actuator is commanded to 100% and none when commanded to 0%.)

Does the scan tool display the status ACTIVE when the actuator is commanded?
--
Go to Step 3
Go to Step 4

3
Is good air flow felt when the actuator selected is commanded from 100% to 0%?
--
System OK
Go to Step 4

4
• Check the actuator that failed for mechanical binding. Repair as needed.

• Check the circuit wiring between the heater and A/C control and the actuator. Repair as needed. Refer to the applicable DTC table related to the actuator for assistance.

Actuator replacement procedures would be shown, from that you could remove them and exercise the doors, but that would not condemn a faulty actuator. Try disconnecting both battery cables and shorting them together. What this does is clear memory and faults. My thinking is, if this is a default in response to a fault, it may correct itself. Mind you if it is a hard fault, it won't take long then for the system to default again. Or, try this recalibration procedure.

Re-Calibrating Actuators After Power Loss
After disconnecting the battery or experiencing a complete power loss, synchronize the electronically operated actuators as follows: •Turn ignition to the RUN position.
•Simultaneously press the AUTO and OFF buttons (located on the heat and A/C control head) for at least five seconds.
•After initiation, the stepper motors will cycle from one stop to the other. You may hear the motors cycling while calibrating.

Factoryjack
Jan 12, 2010.