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Dodge Ram 1994-2001: Air Conditioning and Heater Issues

Your Ram's A/C and heating systems are meant to keep you comfortable and safe in harsh weathers, but what can you do if they go out?

By Jerry Perez - July 8, 2015

This article applies to the Dodge Ram 1500 2nd Generation (1994-2001).

You rely on your trustworthy Dodge Ram to get you wherever and whenever you want, and do so comfortably as well as reliably. A big role in keeping you comfortable is the A/C and heating systems. But if the vents blow warm air instead of cold, or freezing cold air instead of warm, those systems have probably gained a minor or major fault. Diagnosing the A/C or heating systems can get tedious due to their complexity. That's why this article has compiled the most common reasons why your Dodge Ram might not be regulating cabin temperatures properly, or at all.

Materials Needed

  • Small brush
  • UV leak detection system
  • Pressure leak-down tester
  • Voltmeter

Step 1 – Check for debris

Debris might be clogging the A/C system.

Believe it or not, your car also functions as a big container for leaves, dirt, and other types of road debris, which could lead to a clog in several parts of your A/C and heater system. Inspect the cooling and heating components (such as the fan, condenser, and even the radiator) for collected debris.

  • Open the hood and use a small brush to clean around the radiator as well as fan area.
  • Make sure to manually pull out any clumps of debris collected in small crevices, as well as in the area between the engine and the cabin firewall.
Figure 1. Use a small brush to clear out dirt and debris.

If the engine bay is clear of debris, move on to the following step.

Step 2 – Check the thermostat

It could be damaged.

Think of the thermostat you use to read your body temperatures; what if it were to give you the wrong reading? Based off incorrect or inaccurate information, you could potentially treat yourself the wrong way.

The same concept applies to your Dodge Ram. If the thermostat dictates that the engine is colder or warmer than it really is, the rest of the A/C or heating system can be affected and might even fail to switch on or off.

  • Cold start the engine and wait for it to warm up.
  • Touch the upper and lower radiator hoses. If neither of the hoses start to warm up, the thermostat might not be properly regulating the cooling system.
  • Allow the engine to cool down, and then remove the thermostat.
  • Make sure the thermostat isn't damaged or stuck open. If so, you will need to replace it.
Figure 2. Check the thermostat's spring loaded mechanism.

If the thermostat is working, move on to the following step.

Step 3 – Check the cooling and heating system hoses

There could be leaks.

There are a couple of ways to discover leaks in the cooling or heating system.

  • Use a UV leak detection system. The ultraviolet light will allow you to see if any fluids are leaking from the hoses, faulty compressor O-rings, or other cooling and heating components.
  • Check the system's pressure with a pressure leak-down tester. If the reading is too low, you most likely have a leak in the system.
  • You can also take your truck to a local auto parts store since most of them offer free pressure checks.
Figure 3. Example of leak at a hose connection.

If there are no leaks in the cooling or heating system, move on to the following step.

Step 4 – Check the fan motor

It could be dead.

Another item that can greatly affect both the A/C and heating systems is the fan motor. The climate control systems could be working fine, but if the fan isn't doing its job of regulating and forcing cold or hot air into the air ducts, the entire system would be useless. Fortunately, diagnosing the fan isn't very difficult.

  • Start the car and let the engine run for 15 to 20 minutes.
  • Start the A/C or heater, and wait a few more minutes for the fan to start.
  • If the fan fails to start, you can also use a voltmeter to double check that the fan motor isn't receiving power. Replace the motor if it's damaged.
Figure 4. Replacement Dodge Ram fan motor assembly.

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