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fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside

2 edits

Air condition issue

Not the time of the year to be using the AC, but figured I'd post. 2001 Ford Ranger 168k miles 2.5L engine.

In the summer, it happens all the time when I'm driving and the AC is rather unusable. If I have it on Max AC or AC, and hit the gas, the air condition will stop coming out of the vents and start coming out of the defroster. When I let off the gas, a second or two later, it comes back out the vents. Endless cycle. It does this whether I have the heat setting all the way on cold or all the way on hot. Doesn't matter where the heat/cold setting is. It does not do it (at least that I can remember) when it's set to the vents (ie. not AC or MAX AC, but rather the vents, floor, etc.).

You might say, ah, vaccuum problem! Nope. Had a place do a smoke test and it passed. Had the dealer test the vaccuum lines and vaccuum resovoir and they said there's no issue with that.

I have to bring it back again tomorrow and have them keep looking. They're stumped. Not sure why I have to pay a diagnostic fee when they can replicate the issue and don't know how to solve it. Is that normal? I think they said the diagnostic fee will go towards labor once they find a fix, but they don't know how to fix it, and I'm not about to spend hundreds of dollars because of it.

EDIT: And I doubt it's wide open throttle. If I'm trying to maintain 70mph on the highway, it does this. If I have my cruise control set, it does this.

Could it need a new O2 sensor if it's not getting the proper air or dealing with the air properly?


master1000

join:2001-02-22
Fort Pierre, SD
Could be a oneway check valve or a leak in one of the air actuators in the dash. Test each one with a vacuum pump up to 15 inches I bet one is leaking.
--
LET FREEDOM RING


fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside

1 edit
Would they have done that when they said they hooked a tester up to the vaccuum lines that connect to the resovoir, and to the resovoir itself?

BTW, they told me it would be $75 to $150 to fix the issue since they thought it was a vaccuum issue that would consist of either replacing the lines or replacing the vaccuum resovoir. It wasn't, and now I'm probably looking at $150 in diagnostic fees with no solution. I still don't think I should have to pay that.

I went driving again and put the Max AC on (with heat) and drove 2 miles to the store. It was fine. Drove the 2 miles back and at ~40% throttle (ie. 100% throttle would be flooring it), it did the issue that I have described in this thread. Seems to be ok for the first two miles or so, then the issue kicks in and doesn't stop.


Rifleman
Premium
join:2004-02-09
p1a
reply to fartness
Under full throttle many air conditioning compressors shut off to maximize horsepower. Perhaps it defaults to defrost?


MooJohn

join:2005-12-18
Milledgeville, GA
kudos:1
Reviews:
·Windstream
reply to fartness
I'm not familiar with the Ranger directly but most Ford products use vacuum to control their hvac systems, and I still think you have a problem in that area. There's a chance that there is a leak in the control unit (knobs, etc) itself or the hard plastic lines that go to and from the controls.

The system works on pressure, not volume, so it wouldn't take a large leak to cause a problem and it wouldn't have any effect under the hood as far as the engine's operation.
--
John M - Cranky network guy


fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside
reply to Rifleman
said by Rifleman:

Under full throttle many air conditioning compressors shut off to maximize horsepower. Perhaps it defaults to defrost?

This is not full throttle. Read the last paragraph in my last post.


fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside
reply to fartness
Dealer said it's the switch that controls all the functions (ie. max ac, ac, vent, off, vent/floor combo, floor, defrost). They said there's a vaccuum leak with the AC and Max AC, so they have to order a new part. $190 total for part, labor, and diagnostic.


MooJohn

join:2005-12-18
Milledgeville, GA
kudos:1
(wins by 4 hours)



fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside
They said it was causing vaccuum leaks but today when I picked it up after they replaced the switch, still had the same issue. Back to the drawing board.


fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside
They looked at everything again and said the "heater control valve has a slow leak down" on the paperwork. They replaced it for free and it seems to work now.

However, not sure if I have a new issue because of it. If I turned the thermostat or whatever it's called all the way to red (heat), and put it on MAX AC, before it would blow out luke warm air. Now it blows out cold air. When I set the switch from MAX AC to the vent, it works as it should. Did they forget to hook something up, or is it working as intended if it works on the vent (but not MAX AC)?

I know it defeats the purpose but shouldn't running MAX AC on hot blow out hot air? It was before but now it's blowing cold air. I remember other cars I've driven in the past to blow out hot air if I put it on MAX AC.

BTW, the MAX AC setting with it on cold makes it blow out much harder and better now.

It's 40 degrees out too if it makes a difference, but it was same temperature two hours ago before they replaced it, so I don't know why that would make a difference.


Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4
I see you have figured it out. My Jeep GC does the same thing. Applying more throttle diverts the air flow from wherever to the defrost vents. I figured out a few years ago that it is a vacuum issue, but it doesn't bother me enough to spent time or money on it. Mine will do it in heat or AC modes.