My new to me 99 f350 has a great a/c but it only blows on high.
Am I looking at a blower motor, resistor, or the fan switch?

I'm greatful that it does blow on high being in SE TX and SW LA. If it didn't I couldn't ride in the ol girl. A black truck with no a/c is not happening this time of year

 

Here's my new girl next to my dad's obs

 

Sounds like the resistor in the blower housing under the hood. When the resistors burn out it stops working on that speed. There is a different ohm resistor for each lower speed and I don't believe there is one for high. You can ohm it out to check. If they reads open line the resistors are indeed bad.

 

Ok thanks. I'll get that tomorrow.
Also the blower don't move enough air. I can barely feel it when driving. Is this because of the aftermarket blower? I know it has been changed became it has a pigtail on it and the factory one the plug is on the blower

 

Make sure the hoses are still intact.....They're known to rot out after awhile

 

Same thing happened to my truck and it was the resister. If I remember right I tore up the connector getting it apart so make sure its not corroded and your getting full power.

 

At first... I thought this was a thread about the new laws in Washington and Colorado. I saw something the other day that threw me off-balance: You know those people that stand on the sidewalk, twirling signs that advertise a business? I saw a guy on the side of the road with an arrow sign with the lettering "Got Weed?" The times... they are a-changin'.

Fan resistor.

 

LMBO.

 

Yeah, I thought I'd live long enough to see the day.....But 25 years flying a Bucket Truck....Had to be a Good boy. Might have to Retire and become a Gentleman Farmer...

 

Well I finally got around to changing the resistor. Still nothing but high speed. Any more ideas?

 

Yea Tug and Me thinks for the worse!!There are times I just want to get up and choke the crap out of my TV !


Smokie

 

If it wasn't the resistor, it should be the switch. Unless you have rodents chewing wires under your hood/dash.

 

My second guess would be switch, do you have a volt meter?

For the low air flow issue it may be the heater core find are clogged with debris. If you pull the blower you can see it.