Hello There; I just purchased a used 1998 Ford Ranger XLT 4-cylinder with a 5 speed transmission and have a most unusual problem concerning my AC/heater system. It seems when I have either one operating, and I apply full throttle to the gas pedal, the air~flow all "diverts" to the defroster vents!! The air selector switch stays where it's set at, but the air~flow all directs up to the windshield vents..... Is it supposed to do this? I had it in a shop and they said they replaced "something" behind the dashboard, and a vacuum tube under the hood (for $113 dollars), but it didn't do anything. Gosh I just spent all this money on the truck, (I bought it from a car lot with no warranty for $9,600 dolars with 50,000 miles on it)Now I am spending more money on it just to get it to work right. It's a really pretty deep jewel green color with chrome wheels and I fell in love with it. Hopefully someone out there knows what to do with the AC/Heater thing? Maybe it's some simple part I can purchase and install myself? Or maybe 1998 Ford Ranger's are suppose to do this and nothing is wrong? Please e-mail me or post something to help me ok?
Brenda Joan E-mail: medopsgirl(No Email Addresses In Posts!)

 

This was my reply when you asked this question in the other post. If you need more help finding the problem let me know.

The doors that control were the air goes are controlled by vacuum. Defrost is the no-vacuum position so I would suspect a vacuum leak or check valve problem in the system. I bet it goes to defrost when you are pushing the pedal down to accelerate and goes to normally on decel/cruse.

 

>This was my reply when you asked this question in the other
>post. If you need more help finding the problem let me know.
>
>The doors that control were the air goes are controlled by
>vacuum. Defrost is the no-vacuum position so I would suspect
>a vacuum leak or check valve problem in the system. I bet it
>goes to defrost when you are pushing the pedal down to
>accelerate and goes to normally on decel/cruse.

 

Hello There;
Yes! That's exactly what it does! Thank you very much for your reply, so? Now what do I do? Is this a dangerous thing? The vacuum leak? Most Sincerely, Brenda Joan

 

[updated:LAST EDITED ON 18-Jul-02 AT 11:19 AM (EST)]>Hello There;
>Yes! That's exactly what it does! Thank you very much for
>your reply, so? Now what do I do? Is this a dangerous thing?
>The vacuum leak? Most Sincerely, Brenda Joan

not "dangerous"
but alot of stuff operates off vac. one of which is your vent controls. I dont know where to start on vac. troubleshooting
but Ken00 is very helpful.

I had a vac. leak on my thunderbird it gave me a check engine light for 2 years no one could find the dam leak but i finally traced it to a leaking pcv valve grommet (UGH) cost like 2 bucks to fix.
This probably isnt your problem i would think you have a vac. line off or a broken T or something. That sounds like a huge vac. leak to change the vent settings under accel.

If you arent mech. inclined I would just take it somewhere and tell em you have a vac. leak if you know a good garage it shouldnt be very much to fix. just dont let em sell ya a bunch of crap and tell em if it dont fix the problem you arent paying for it.

Rand

Edited:
NOTE: when i said garage I didnt mean a Midas or a goodyear place they would probably rape your wallet for a 100 buck diag. and then a bunch of other crap.

 

Thanks again Rand..... Goodyear? Yep that's EXACTLY where I took it! After getting "eyeballed" by every mechanic and tire changer in the place, they kept the Ranger for 2 days, (I had to take a cab to and from work which cost me even more money Might be a little garage here in town I can take it to. I live in a small town, the Goodyear guys are up the roads a ways in a larger town. Anyway, maybe I can have a peek under the hood myself? Look for something that doesn't appear "not quite right" and maybe motor up to a Murray's or AutoZone car parts place in a bigger town and buy some things to try? Oh yes, by the way? How do I contact Ken? The guy you said knows more about vac systems? Again Rand, I do appreciate your help. Don't have a boyfriend and the guys at work,(Doctors, interns and medical people) while trying to help, don't know anything about cars or trucks. (Not a "Good Ol' Boy, common sense guy" in the lot of them!) Anyway, thanks ok? Sincerely, Brenda Joan

 

Check under the hood (motor OFF) and look for any obvious disconnections. There are several smaller hoses on the intake manifold (big silver metal thing with four "legs" on right side of motor). The biggest hose goes to the power brake booster (big metal can in front of driver). Check for any hoses (not wires) that aren't connected and have an open nipple nearby. PCV valve is deep down on right side and hard to spot. Let a tech. check it.
Also, has there been an aftermarket radio install done on this truck?
If the original radio was changed out for a CD, etc.(maybe by the folks that sold it?), there may have been a hose knocked loose during wiring (the a/c controls are right under the radio).
Just thinkin' and guessin' at this point. Try to find a good Ford mechanic and stick with him.
CB

 

Hi CB;
Thanks for the advice. Nope, radio is a stock Ford unit, not "aftermarket". I did poke and probe a bit yesterday during my lunch hour, sluthed out what could possibly pass as vacuum lines going to various and sundry vacuum accuated things and so forth. Seen that big can by the brake stuff you mentioned and did follow lines coming off the alloy thing, (manifold?)I traced this gray thin line coming out from under the "firewall"? to these two big AC lines. (little thin gray tube plugs into a valve type thing), and when I pulled the gray line off and stuck my finger over the "nipple" it "sucked", (which means vacuum I take it?)Looks like someone did a split repair on it at some point in time, however? I did have the truck running with the AC on and it didn't make any difference when I had it unplugged or not. At idle, everything works as God and Ford had intended. Maybe something at that valve is suspect? Anyway, guy up in Grant's Pass Oregon suggested I spend some "quite time" listening for "noises" and since I have the weekend off, (no dates or other distractions) I will do this, also repair a nail that got destroyed during my lunch hour "engine diagnostics". Anyway, after lunch I returned to work with grease and grime up to my elbows! Everybody asked what the heck I was doing? Working on "trucks"? I said yes, as a matter of fact I was! Have a great day!
Brenda Joan

 

I am not to farmilliar with the lay out on this year of truck, but there should be a can ( kind of looks loike a coffee can) probably on the passanger side of the truck on the fender this can will have at a couple of lines connected to it, and it should have a little round check valve on one of them also if that check valve goes bad it will cause this problem or if the can is leaking it will also cause the problem. I am sorry I probably am not explaining this well, if you take it in some where ask them to check the vacume canister ond the check valve.
Hope this helps some. What area are you located in?

Scott

 

Hi Scott; Yes as a matter of fact I seen this very "check valve" on that big "can" yesterday, (when I was poking around under the hood)and thought "maybe that could be a possibility"? Thanks for your suggestion, I'll motor up to a Murray's Auto Parts in the morning and get one and try it. Does the thing just unplug? Didn't look too complicated.... I live down in a small, sleepy semi~resort town off the lake. Not much around here except a few shoppes, churches, some lonely country & western bars and a (really good) restaurant up on Main Street, then it turns into pretty country lanes just outside of town, then out to the area hospital where I work. Thanks for your advice ok? Have a great day Brenda Joan

 

>Hello There;
>Yes! That's exactly what it does! Thank you very much for
>your reply, so? Now what do I do? Is this a dangerous thing?
>The vacuum leak? Most Sincerely, Brenda Joan

Hi Brenda,

The engine creates a vacuum in the intake, this is the source for all vacuum. The vacuum for the climate control runs from the intake over to the reservoir, which is under the coolant and washer fluid tanks. The reservoir has a check valve that maintains vaccum in the reservoir when the engine has low vacuum. I would suspect this valve as the problem if you don't have any leaks in the hoses. To test for vacuum leaks you need a vacuum gauge/pump. To test the reservoir disconnect the outlet hoses and pull a vacuum of 15 and see if it loses more than 1 per minute. If it does the reservoir is bad. From the reservoir it runs into the cab and to the climate controls on the dash. From the climate controls it runs to the vacuum motors, that control the air flow doors, and to the valve in the heater hose, that controls coolant flow to the heater core. You would check the vacuum motors in the same way as the reservoir. Hoses can be capped at one end and tested too.


This may sound hard but it really isn't that bad to do. I would suggest finding a better shop, this is a basic repair. If you need any additional help feel free to email me, there is an icon near my screen name. I will be on vacation until 7/28 and won't be picking up my emails.

Ken

 

Hi Ken: Thanks for your reply. Sounds a bit complicated though. I did just call a Ford dealer and asked the parts guy about a thing called a Solonoid Cannister Purge Valve? ($39 bucks) but this thing is located on the Vaccum Cannister, and not where you mentioned, so I think your talking about something different. Ok, what I will do Saturday is put on some old jeans, a tee shirt, tie up my hair in a ponytail, (baseball cap optional) and latex surgical gloves and have a look at where you mentioned. Maybe something just came off? Or has an obvious crack in it or something? I'll check it out. You know? I bought this truck a few weeks ago and also suspect it got banged up pretty good on that side, (where all the stuff you mentioned is located, passenger side)so maybe that valve or whatever got kind of banged up also? Well, I'll crawl under my lil' truck in the morning, (my prime and proper small town church lady neighbors are going to have a field day watching me do this!). Thanks again ok? Sincerely, Brenda Joan P.S. Didn't see the E-mail icon Ken, but mine is medopsgirl(No Email Addresses In Posts!) if you care to e-mail me? Thanks again, I am determined to solve this problem yet!

 

Check your mail.

 

Next time clean your motor BEFORE you work on it and you won't have those dirty hands. Can't help with the nails, though. But seriously, I think the vacuum cannister is a good candidate. And I trust Ken00, just don't tell him. The amount of vacuum generated by the motor increases with demand, so when you let off the gas there is no longer a "vacuum starvation" issue and things work right. The long term effects of a leaking vacuuum line can hurt your motor, i.e. running lean, rough idle, burnt spark plugs (a bitch to replace on your motor, I know 'cuz I have the same one). So this isn't something to get used to and live with.
Check that check valve and go from there.
CB

 

Brenda,
You might also want to spend a couple bucks and pick up a Haynes manual for your year of truck. They are written well, and will help you get to know what your truck is all about. i have one for my Bronco, my wife's Ranger and my MGB. All three have more than paid for themselves many times over in showing me how to fix things properly myself. Besides saving money, you'll get a great bit of self satisfaction knowing you did it yourself.

have fun!

Paul