AC cuts off when accelerating

[Uncle Gump]

Well as stated... defrost position is the default. You loose vacuum to the vacuum motor... it will fail in the defrost position. Vacuum or lack of shouldn't have anything to do with the fan motor.

 

[RonD]

Do this
Select Defrost on the Climate Control and put fan on High, make sure you can feel the air flow from the defrost vents
Then drive, Test if air flow stops thru Defrost vents when accelerating, if so its IS a blower/fan issue

If not then select Panel Vents and repeat test, now that you know what Defrost flow feels like, if flow diverts to Defrost vents then its a vacuum issue


There is no logical connection between blower/fan operation and engine/vehicle accelerating, like with Vacuum
But a loose connection may be effected by motion, a longshot for sure but not a no shot

 

[Dirtman]

Yup no correlation between engine load and the actual blower motor. Another long shot, the resistor about to die, but it should still work on high. Gotta be a ground or wiring issue.

 

[Lemarque]

Do this
Select Defrost on the Climate Control and put fan on High, make sure you can feel the air flow from the defrost vents
Then drive, Test if air flow stops thru Defrost vents when accelerating, if so its IS a blower/fan issue

If not then select Panel Vents and repeat test, now that you know what Defrost flow feels like, if flow diverts to Defrost vents then its a vacuum issue


There is no logical connection between blower/fan operation and engine/vehicle accelerating, like with Vacuum
But a loose connection may be effected by motion, a longshot for sure but not a no shot

Just saw your post. I'll try it in a couple of hours

 

[Lemarque]

Do this
Select Defrost on the Climate Control and put fan on High, make sure you can feel the air flow from the defrost vents
Then drive, Test if air flow stops thru Defrost vents when accelerating, if so its IS a blower/fan issue

If not then select Panel Vents and repeat test, now that you know what Defrost flow feels like, if flow diverts to Defrost vents then its a vacuum issue


There is no logical connection between blower/fan operation and engine/vehicle accelerating, like with Vacuum
But a loose connection may be effected by motion, a longshot for sure but not a no shot

Vacuum issue!

I'll ask my mechanic to check as was suggested:

In the engine bay there will be a grey and a black hard plastic vacuum lines coming out of firewall on passenger side
Black one is the main line and runs forward to the Vacuum reservoir in the lower front of engine bay

Still healing from a fractured left hand or I'd give it a go myself.

TVM

 

[Uncle Gump]

Ouch on the fractured hand....

Knowing what is going on with the A/C does prevent another trip to your wife's podiatrist getting her foot out of your bum though.

 

[Lemarque]

Ouch on the fractured hand....

Knowing what is going on with the A/C does prevent another trip to your wife's podiatrist getting her foot out of your bum though.

"Proctologist" But it's not a problem; I've met my medical plans deductible. And he checks my prostate at the same time

 

[Lemarque]

Arrgghh....

So the mechanic is a guy I trust, been in the business 25 years. He says he "didn't do anything" but check the hoses.

Now the fan only blows thru the defrost and foot well not the vents on the dash. And NOW THE HEATER DOESN'T WORK! That is, no heat even to defrost or footwell.

Will donate to your favorite charity for a fix.

 

[RonD]

The heater not working may be the blend door, a common issue on Fords, its electric, but FIRST check the heater by-pass valve in the engine bay

The By-pass has 4 heater hoses connected to it and a vacuum controlled valve
It will have a Grey hard plastic vacuum line connected
Start engine
In the cab select any setting EXCEPT OFF or AC MAX
Now go to engine bay and pull off the Grey line from the by-pass valve, it should NOT have vacuum, put you finger on it, you will feel if there is vacuum present
If so that's why there is no heat, plug that vacuum line and leave it off, you can deal with it later

If there is no vacuum on the grey line then problem is the Blend door
Also feel the heater hoses at the firewall are they warming up, or hot?
That means by-pass valve is open and hot coolant is going thru the heater core in the cab

Google: Ford Ranger Blend Door
Loads of videos on this issue

The blend door's electric motor is controlled by the TEMP knob, the blend door channels air from the fan thru the heater core(HOT) or around the heater core(COLD) or anywhere in between


As for the Vents
There are 2 Vacuum "motors" connected to 2 vent doors that control air direction to Defrost, Panel or Floor

Diagram here: https://www.explorerforum.com/forums/attachments/hvac-20diag-gif.41768/

Defrost is the NV(no vacuum) setting for both vent doors
Panel is when V(vacuum) is at the one vent door but not at the other vent door
Floor is when there is vacuum at the one vent door but not the other(defrost door)

Defrost mixed with floor would mean no vacuum at defrost door and PV(partial vacuum) and other vent door

Can't tell you why its stuck that way, there is a vacuum manifold on the back of the panel and then another multi-vacuum line connector next to left side of glove box
If you fold glove box down all the way you can often see it, multi-colored vacuum hoses

This is the rear of the climate control panel: https://i.ebayimg.com/images/g/1YYAAOSwsBhfQB3e/s-l500.jpg
On the lower left you can see the multi-colored vacuum hoses, white, yellow, brown, blue, red

Maybe you have a leak there or at the connector by glove box

Did the mechanic check vacuum level?
You need a vacuum gauge to test if you are getting above 12" full time, usually it holds between 15-20"

 

[Lemarque]

Just a quick reply. I've run this by my mechanic; but to fess up, for almost 25 years I turned wrenches. Towards the end of my 'career' I managed more than anything.

This darn hand of mine and the fact that my ancient SnapOn tool box is missing more than my 10mm wrenches, has me at a disadvantage.

Worse comes to worse, I inveigled (is that a word) from the dealer service writer, when I took it there a week ago for an airbag recall, who the best tech in their shop is. So if I must, I'll run it by there.

I will however check what I can of you very much appreciated reply.

All the best

 

[Lemarque]

So...

Lesson learned. Find a mechanic who'll "go after it" for lack of a better expression. The blend door replaced but that wasn't it.

I bit the bullet and made a appointment with the dealer. The tech put it up in the air and found the hose was bad about 8 inched from the reservoir. Thar she blows!

Thought I'd upload this since it is a Ford community. Even tho it's from across the Pond. More pics if anyone's interested.