a/c fan stops and starts at random...help!

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chrishennig
Posts: 10
Joined: Fri Dec 19, 2014 1:29 pm

a/c fan stops and starts at random...help!

Post by chrishennig »

Hello all. I tried researching to see if anyone elses symptoms matched mine, but I didn't see a similar case yet. Sorry if I missed a thread about this...

I replaced the blower motor in May of 2014. Also fixed the interior circulation "clicking" problem at one point.

This new problem is concerning the fan. It starts and stops at random. When it works, it blows on all fan speed / settings. For a while, when it would stop, I could turn the switch on and off several times and it would start back up. Could this mean the 2.5 year old blower motor is already going bad?

It'll go days without running. And then, like today, I tried turning it on several times, didn't work until 2 hours of driving around.

Anyway to diagnose?

The a/c itself isn't the problem. While the fan isn't working, I can activate the A/C, and cold air slowly comes out just from exterior air intake. Same with heat, if I switch the thermostat to heat, temp is fine.

Thanks for any suggestions!
TAnderson
Posts: 1
Joined: Sat Jul 07, 2012 4:39 am

Re: a/c fan stops and starts at random...help!

Post by TAnderson »

My 2005 did this. Id hit the area of motor and would start up. Run for some various amt. of time. Finally quit. Problem was fan motor electrical connection. Intermittent contact, arcing and burned contact surfaces. Replaced. Solved problem.
jolt
Posts: 945
Joined: Sun Mar 02, 2014 2:07 am
Location: Twin Cities, Minnesota

Re: a/c fan stops and starts at random...help!

Post by jolt »

Both of you are describing worn out/bad brushes in the blower motor. If you tap on the motor and it takes off running, you most likely have bad motor brushes. At least that is the part that physically wears out on a DC motor. You could have bad wiring connections but the odds on favorite in this case is bad brushes. The blower motors in cars do not have replaceable brushes any more like the 1950's and 1960's cars did, and the whole motor must be replaced.
302LVR
Posts: 56
Joined: Tue Mar 01, 2016 2:04 pm
Location: South Florida

Re: a/c fan stops and starts at random...help!

Post by 302LVR »

^^^Agreed! I'd also like to add that you can always start troubleshooting the problem with smaller, less expensive parts first like fuses, relays, Resistor, and even opening up that motor and cleaning the contacts with starting fluid or electrical contact cleaner spray or something. Dirty contact area or relay blades not making proper contact have given me issues in the past and i've fixed the issues by cleaning up contacts or closing those relay female connectors in the past to make better contact. Hope that helps.
chrishennig
Posts: 10
Joined: Fri Dec 19, 2014 1:29 pm

Re: a/c fan stops and starts at random...help!

Post by chrishennig »

So I had ordered a new fan and resistor from Amazon before inspecting everything.

I disconnected, used electrical cleaner and compressed air to clean the connections.

Put the old fan back in...and it worked again...it seemed like a lose connection where the cable plugs into the fan.

I unplugged it to inspect again and the cable coming from the car looks charred...?! Could that have been from the electrical cleaner not drying?

But...if you wiggle it, the fan still works and has been working since I plugged it back in...

Sorry I don't have a picture at the moment, I can post one on Sunday.

I have a feeling it'll cut out again after a few bumps. How would I replace the bad connector on that cable? It seems like a very unique part/connection.

Thanks for any help...I can trade National Park travel advice for electrical advice as I have 0 electrical skills...
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