Skip the auto shop - Our mechanics make house calls

Q: i have a 2005 gmc c5500 the heater motor comes on for 20 sec when first start truck then nothing

asked by on

i have a 2005 c5500 heater motor comes on for 20 sec when i first start truck then nothing
My car has an automatic transmission.

Hello - I suspect this may be a problem with the fan motor resistor pack. If the fan control is put in the "Max" or "High" speed position, does the fan continue to run? Does the fan only run for 20 seconds, then stop in the Low and/or Med fan speed positions? If the answer is "Yes" to these 2 questions, the heater fan resistor pack is bad, and needs to be replaced. I would recommend having a Heater Is Not Working Inspection completed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose this problem, get an accurate assessment of the damage and provide an estimate for repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  • Home
  • Questions
  • i have a 2005 gmc c5500 the heater motor comes on for 20 sec when first start truck then nothing

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: TC light on during slow driving, noisy braking

Hello. When this occurs on your vehicle it is usually caused by a bad wheel speed sensor. These tend to show up more during low speed driving. It may also be a bad yaw sensor. Since the light is...

Q: pads are 2mm on 2014 yukon xl denali with 52000 miles...all works good...incidental finding...do I replace now? Pads and rotors? o

At 2mm, the pads are definitely due for replacement. The the thickness of the brake rotors should be measured and compared to the minimum thickness specifications. If they measure above the specs and there is enough thickness to them, resurfacing...

Q: how do i fix the air conditioner from blowing cold for a minute then warm?

If the air conditioner fuse is blowing, then there is a high electrical draw probably from the a/c compressor. This ca be due to an electrical short, or the a/c system can be over-charged causing the compressor to draw too...

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...