Are you tired of fogged-up windows, no heat, and musty, unhealthy air inside your Dodge Ram truck? Fed up with repair shops that can't fix your Ram truck heater problems? Or maybe create more problems than they fix? Here is an example of a common Dodge Ram truck problem that suffered at least two failed attempts to repair before it arrived at our repair shop.
We will repair your Ram truck heater problems quickly, correctly, and economically. We know Ram trucks inside and out, top to bottom. Guaranteed heater repair, fast.
Table of Contents
Reason for Customer Visit
Problem
Diagnosis
Cause
Repair
Best Practice
Cost
Tips
FAQ
Recommended Dodge Ram Repair Shop
Reason for Customer Visit
Have you ever taken your vehicle to an auto repair shop, and they charged you a lot and didn't fix it? Or worse, they created more problems than they fixed, then didn't want to fix the new problems they created... or couldn't fix them.
We see many vehicles suffering from poor diagnoses and bad repairs. Often, this is due to vehicle owners attempting DIY repairs or taking shortcuts in a misguided effort to save money. Problems resulting from other repair shop work are often caused by a lack of technician skill, outright incompetence, or not having the equipment to make a correct diagnosis and repair.
Either way, lousy diagnosis and faulty repairs can be very costly. They are mostly a BIG waste of money and provide very poor value. After over forty years in business, we have developed a policy of fixing problems correctly, or we don't do it. The repair doesn't need to be “like new,” especially for older vehicles, but it must be safe and provide the best value for the customer.
A new customer brought us a 2013 Dodge Ram 5500 service truck with a heater problem. Like many vehicles with complicated issues, there can be a long history of service neglect and incorrect or inadequate repairs. This vehicle was no exception.
The heater had not worked correctly for a long time, gradually worsening until it finally quit working. It had reached a point where driving in winter road conditions wasn't safe.
The truck had been working out of town, and they had a repair shop in that area attempt to fix it. After the repair, the heater fan ran on the low-speed setting, and the air was barely warm. Also, no air was coming from the windshield defroster vents. The worst issue was the fan did not turn off with the ignition key, and the battery died if the driver did not remember to turn the fan off when the vehicle was parked. To add insult to a very high repair bill, the shop didn't fix the original cause of the problem.
The owner asked if we could fix the heater as it was designed to work. We guaranteed him we would fix it correctly, or he wouldn't have to pay. And we would do it as fast as possible.
Problem
The driver reported that the heater fan only ran on the low-speed setting, there was no hot air at the vents, and the fan didn't turn off with the ignition switch.
They also mentioned that after the truck was taken to the previous auto repair shop, the fan would only run on low, the air was still “smelly,” the airflow to the vents was very weak, the defrost air never got hot, and the windows would always be fogged with moisture on the inside.
Diagnosis
Our service advisor quickly confirmed that the heater blower motor ran with the ignition key off. The Blower fan would turn off when the fan was switched off, but the key should turn off all vehicle accessories to prevent the battery from draining if the driver forgets to turn them off.
The customer approved the first level of diagnostic testing we recommended, and our Dodge Ram technician began diagnosing the heater fan electrical system.
Our diagnostic testing is charged in blocks of time. After each diagnostic stage, the customer is contacted with a report on the technician's findings and what further action is required or an estimate for repair supported by a report including photos and videos.
The technician confirmed that the heater fan on this truck operated if the heater blower fan was switched on regardless of the ignition key position. Next, they tested the heater fan relay with a known-good relay and found no change. Then, they removed the relay entirely, and the blower still ran when switched on. This indicated the fan was getting power from outside of the normal fan power circuit.
Our service advisor text-messaged the customer with an update about the diagnosis and advised them that the problem would need further time to diagnose. The customer approved a second block of diagnostic time.
Next, the technician removed both the blower motor fuse and the HVAC system fuse, and the blower motor still ran when switched on. Suspecting an electrical short in the power feed wire, they started working backward from the blower motor towards the battery to find where the power was coming from.
When the technician reached the blower speed control module wiring connector, they could see corrosion spreading from where the module fits into the heater HVAC housing. They removed the module and found it was corroded by moisture and dirt buildup inside the HVAC housing. Next, they replaced the module with a known-good module, but the power supply problem still existed.
Continuing to follow the power supply wire, the technician found that the fan power wire at the electrical distribution box under the vehicle hood had been cut and connected directly to the battery. This allowed the fan circuit to bypass the ignition key master shut off! Next, the technician disconnected this bypass wire installed by the other shop, and the blower no longer ran. Our technician temporarily connected the original factory wires to confirm their diagnosis, and the fan operated as originally designed.
Cause
The cause of this Dodge Ram HVAC blower fan problem was solved by following a correct step-by-step diagnostic process. Our technician knew how the HVAC blower fan electrical system should work, how the system was wired, what components were involved and where they were located, and how each part should be tested. This knowledge allowed our technician to quickly and accurately find and fix the problem correctly. No poking around, hoping to stumble across the source of the problem.
The original problem was caused by accumulated dirt and debris in the HVAC housing. This vehicle operates in extremely dusty off-road construction sites, and the HVAC air filter had been removed and not replaced sometime in the past. This was probably done because the filter plugged so quickly. The lack of a filter allowed dirt and debris to accumulate in the HVAC housing. This dirt then absorbed moisture, which condensed on the inside of the housing when the heater was used, eventually causing the corrosion and failure of the fan control module.
This moisture problem was further complicated by the HVAC filter access door being broken sometime in the past. The large hole in the housing decreased the airflow through the housing, worsening the moisture and corrosion problem, not to mention the resulting poor window defrosting and dangerous driving conditions it created.
We suspect the original heater problem of a corroded wiring connector on the heater fan speed control module was caused by not using a cabin air filter. Moisture then saturated the accumulated dirt and debris in the heater housing during the wet months and caused the blower speed control module to corrode. The heater housing was probably damaged in a desperate attempt to get air flowing through the plugged cabin air filter. Then, another previous technician, probably not familiar with the fan wiring, thought they could fix the fan power module problem by wiring the fan directly to the battery.
We often receive vehicles repaired incorrectly or damaged by previous repair work. Usually, it is a DIY do-it-yourself repair or a technician who does not have the training, skills, or experience to repair it correctly. We find weak diagnostic skills are the leading cause of poor repair work.
After their diagnosis, our highly experienced Dodge Ram truck technician recommended permanent wire repairs, replacing the blower fan control module, cleaning and repairing the HVAC housing, installing a new cabin filter, and reassembling and performing a final test of the heater fan system.
Repair
Our Ram truck technician removed necessary components to gain access to the wiring underneath the battery power junction box and performed repairs to blower motor wiring. Permanent wiring repairs were done so they would withstand the vibration of the rough roads this vehicle is used on, and the high power demands of the heater blower fan. They then reassembled any components removed during repairs.
Parts used were solder-type wire connectors and self-sealing shrink tube wire protection.
Next, our technician removed the necessary components to gain access to and replaced the blower motor control module. They removed the accumulated dirt and debris and washed out the heater housing. Next, they repaired the damaged heater housing, installed a new cabin air filter, and a new filter service door. They reassembled any components removed during the replacement of the blower speed control module and performed final testing to verify the heater was functioning as designed.
The parts replaced were a new HVAC Blower Motor Resistor Module, a new Cabin Air Filter Cover, and a new Cabin Air Filter.
Best Practice
Since this vehicle spends extended periods idling when parked on dusty construction sites, the cabin air filter may quickly plug with dust and need frequent replacement. The restricted airflow caused by a clogged air filter will also cause the HVAC fan speed control module to overheat and fail more often.
Vehicles operating on industrial or construction sites need more frequent heater housing cleaning and cabin air filter replacement. We cautioned the vehicle owner that if the cabin air filter is not kept in place and frequently maintained, this problem will happen again. We recommended that the cabin filter be inspected, cleaned, or replaced each month during the dusty spring, summer, and fall seasons.
Cost
Dodge Ram heater problem diagnosis and repair costs are difficult to estimate due to the numerous causes and required repairs. Once the problem is diagnosed, we will happily provide a Dodge Ram heater repair cost estimate.
Tips
- Dodge Ram trucks in a dusty environment may need frequent cabin filter replacement and heater housing cleaning.
- A plugged cabin filter restricts airflow through the heater, which can cause the heater fan speed module to overheat and fail.
- Debris in the heater housing can jam or break the heater housing blower door, preventing air from flowing to the vents.
- Regular engine coolant replacement will prevent corrosion of the heater core and lower output air temperature.
FAQ
Why is my Ram truck heater not working?
There are two main causes for Dodge Ram heaters not working. The most common Dodge Ram heater problem is the heater fan not working or only working on some speed settings. The second most common Ram heater problem is low coolant level.
Why won't my Ram truck heater fan work?
A failed fuse is a common reason for the heater fan not working. The second most common reason for the Ram truck heater fan not blowing air is a heater fan speed control module failure. The third most common heater fan problem is dirt or debris buildup in the heater box or a plugged cabin air filter which prevents the fan working on all speed settings.
Why is my Ram truck blowing cold air when the heat is on?
There are three leading causes of the Ram truck heater blowing cold air:
- Low Coolant Level. If there isn't enough coolant in your Dodge Ram engine cooling system, hot coolant will not reach the heater core, and it will blow cold air.
- Malfunctioning heater blower door is another common cause for the Ram heater blowing cold air.
- Defective engine thermostat is another common cause of low heater output temperature and Ram heaters blowing cold air. A failed engine thermostat usually also triggers a Check Engine Light.
Is it worth flushing a heater core?
Heater core problems are common with Dodge Ram trucks, but a plugged heater core may not be the problem and may not be a good repair value for a low heater output temperature problem. See this article for more information: Is Dodge Ram heater core flush needed
Recommended Auto Repair Shop
Why State Street Auto Service in Whitmore Lake, MI
We've Got The Experience
We know the common problems Ram diesel trucks have. We've been there and done that—many times. This experience makes our Ram truck problem diagnosis fast and efficient, saving you money.
A large part of our business is medium-duty diesel trucks. Lots of Dodge Ram Cummins. They get used hard. Often just from the symptoms you describe we know exactly what your problem is. No guessing in our shop!
And if you have a difficult problem our Dodge Ram technicians have the skill and experience to quickly find and solve your problems.
Training
Our Dodge Ram truck technicians are automotive technicians first with extensive diesel repair training. Light and medium duty diesels have different problems from heavy-duty big rigs. Our technicians are truly specialists that have skills gasoline automotive technicians don't have. Don't trust your expensive diesel truck to technicians who don't have the expertise and experience with light-duty and medium-duty diesel vehicles.
Value
For our commercial fleet customers the value we offer is speed of service. When your vehicle is not working your repair cost is not just what we charge you. The greater cost is often your lost revenue and costly employees who are sidelined and not doing their job. That cost adds up quick! We prioritize our commercial customers, have the skills and expertise to get your repairs done fast.
Speed
Our experience, equipment, and skills allow us to get your vehicle back on the road as faster than other lesser capable repair shops. We also have many commonly used parts in stock so that we don't have to wait for parts. That repair speed is where we can provide the greatest value to you.
Cost
Your highest cost repair is one that has to be redone, or worse, doesn't solve your problem. Avoid repair shops that don't know what they are doing. Patch-ups and shortcuts may look like they are saving you money but they are poor value.
The repair highlighted in this article is a good example of how technician incompetence and poor repairs can cost you big dollars. Both in time, lost productivity, and dollars spend on worthless repairs.
Not to mention the damage that incompetent repair work can cause. Diesel parts are very expensive, and labor costs can be massive, especially when a poor-quality repair job has to be redone. Don't fall into the trap of cutting corners that don't last or cause greater problems. That is very poor value.
That said, we won't recommend a repair if the vehicle doesn't warrant the expense. If we don't feel the work we doesn't provide long-term value we will say so. Our reputation means more than a quick cash grab!
Our Best Offer
As Larry The Cable Guy says we 'get er done'. As quickly as needed. As best as required. And as economically as possible. That's value. That's smart fleet repair management.
Don't waste dollars trying to save pennies. Penny wise and dollar foolish is not good value. Especially with diesels!
Contact us. Now.