Cadillac Brougham heater issues!?

Question

I have an 89 Cadillac Brougham. 307 v8 vin code Y. I recently had the blower motor, and a/c control module replaced in the car. My problem is that I still dont think the controls are functioning properly. On the dash control panel I have the temp adjusters, economy, fan low, auto, fan high, and defrost. The issue I'm having is when I turn the car on.... even after I let it warm up to operating temp... I can only get the heater to start blowing if I put it on defrost first. After I get the fan to start blowing, then I can switch to economy, or auto, etc.... In other words, if the car is turned off, when I restart it, I get nothing from the vents untill I let the fan spool up on defrost. This can't be the way they work right? I just dumped a ton of $$ on the module and fan and it should be working correctly!

Answer 1

Cadillac's have Automatic Temperature Control systems which are extremely complex and require a vast knowledge to diagnose.



The good news is that most of the time the source of the problem will be a vacuum leak. Your system has vacuum operated air conditioning controls. When you have a vacuum leak, the first thing you notice is that the controls will not work properly.



The most common vacuum leaks occur by:

1. A disconnected vacuum line

2. Cracked or leaking vacuum lines



The source of the vacuum is the engine. So you will notice that there are several vacuum lines in the engine compartment and even some that go through the firewall that feed the vacuum for the HVAC controls. Inspect all these lines. Check for any that have been disconnected by the engine vibration. If none are disconnected, check the condition of the lines. These lines are thin rubber lines and will turn brittle and crack over time with the engine heat. If you find a bad line, then you can easily replace the bad section by purchasing a foot of vacuum line from your local auto parts store. If you can't find the source of the leak, you may want to take it to a mechanic to diagnose. They should have the equipment to check the diaphrams and actuators in your ac system.



Hope this helps.

Answer 2

The only way that you are going to find out what is wrong is to do a complete check on the (ATC) because you could have a bad in car sensor, aspirator, programmer, vacuum line or an open circuit.

Answer 3

once you assert it slips out of components do you advise the kit shifter is slipping ?The engine shutting off might desire to be interior the steerage column wiring or ignition i might examine the thick black floor twine and the steerage column wiring harness bec those grounds tend to have problems and so do the harness's surprisingly if it has tilt steerage. wish that facilitates and better of success.by how wires tend to get pinched and that's no longer that extensive of a activity to restoration it in basic terms takes time and persistence.