Im looking for a repair manual for my ford ranger that technicians use to diagnose problems. I dont think its the regular chiltons or whatever repair manual (I really dont know). Im training to be a auto technician now and something weird is going on with my a/c blower fan so i'd like to try to figure it out myself.

 

Hmm I dunno of a book that teaches you to diagnose, whats the problem and maybe I can point you in a direction and you can figure it out? Always remember the basics, check fuses, check for power, check for ground, check relays.

 

well, im going to a technical college now to be a technician, and we were using repair booklets that have all the diagrams, and charts that have tests to do if (insert problem here) isn't working. Im not sure if thats how the manuals are that technicians use or not.

 

Ohhhh that explains alot. I dont mean to be rude but a technician really doesnt use a "manual" on how to fix a car. Its more or less finding out what the problem is, saying ok I have this problem ie ac blower only blows on first 3 settings but doesnt blow harder on 4th setting. There is no repair book that I know of that would say "oh well its the switch not making good contact on the fan control, get a new fan speed switch".... Now there are times I look in alldata to look up TSBs, and see like Ok the PCM knows top dead center when these 4 sensors tell it so. But nothing will tell you exactly how to test sensors or how to diagnose. Its all about feeling and knowing how a system works. My friend is going to UTI (universal technical institute) and he is the same way you are. In class they tell him all this stuff and fancy words, but once it gets time to working on a real car, its competely different. In other words you need hands on time to really learn to diagnose.

In a repair shop, you dont really get the luxury of sitting down with books telling you how to repair cars. It is not efficent nor practical so I wouldnt make it a habbit. Assuming you just started school I would say give it time to learn more about how an A/C system works, and electical systems too before hand..

Dont get into the practice of relying on books to tell you what to do. I really dont mean to be rude or mean. Just saw the same thing from my friend relying heavily on Alldata and looking to it instead of looking at the car and using his imagination.

 

Yea, I kinda figured it wasnt that easy. I've heard that there is a (whatever you call it) that tell the voltage or whatever of a sensor or part when its working right. My problem is that I dont know how the rangers a/c system is set up. It acts like the blower is operated by vacuum because if you mash the gas all the way to the floor, about 5 seconds later, the blower will stop blowing air out of the vents, then when you let all the way off the gas, or push the clutch in and the rpms drop, about 3 seconds later, it will immediately start blowing at the fan speed it was before. It will not stop blowing at all if I let it sit and idle. I also need to look at the IAC (I think) that controls engine rpm, but I dont know where it is on the 4cyl.

 

Voltmeter

A/c is designed to cut out at Wide open throttle like you described, it is in order to get the most power to the ground.

I dont quite understand this.

 

That is almost right.

The blower isn't operated by vacuum but the doors that direct the airflow are. When the vacuum in the HVAC controls drops, the discharge defaults to the defrost vents. This makes it seem like the blower is turning off but, in reality, the A/C discharge is being temporarily diverted to defrost mode.

To prevent this, the system has a vacuum reservoir and a check valve to maintain vac to the HVAC controls even when the engine vacuum drops off. Your system either has a leak in the reservoir or lines or the check valve isn't working.

Even if the WOT cutout is activated, the blower should continue to blow from the vents if that is what is selected on the mode switch. The air may become warmer during extended WOT operation but the airflow from the panel vents will not stop.

 

It will do it just cruising down the road too, it will just do it quicker if you mash it to the floor. I've never seen it act like this in anything else i've drove. Also, if I turn the a/c off, and then back on, it takes a few seconds for it to start blowing, however, if its idleing, it will come on immediately.

If I shift at low rpms like around 3k, the rpms dont immediatly drop, it kinda freezes for a second or 2, and then slowly drops, and when I slow down coming to a stop, the rpms will drop to around 600, and then come back up. However, if im sitting still idling, and rev it, the rpms come back down quickly. I dont know, someone said there did it and it was the IAC, but I dont know where it is.

 

Could be IAC or MAF. I would spray some carb clean down your throttle body making sure to get it into the IAC port.

yeah Listen to what rwenzing says too, I thought you ment it stopped blowing cold when you get it wot. Im leaning towards check valve.

 

With the engine running or not?

Thanks for the help so far......so where should I start looking? I was thinking at the back of the HVAC control switches, since i've been working on the radio and stuff back there a few times (although I guess I should start at the easiest place and go from there, but I dont know where the check valve or resovour is). This is the first or second time i've used my a/c probably since I got the truck last september (longer than a couple minutes) since it hasn't been that hot up until now, I usually just roll the window down. I've only been at tech school for a quarter now, and I haven't gotten into the a/c class yet, so I dont know how the a/c system is set up to work. I just figured the problem had something to do with vaccum the way it was acting, I just didn't know what.

 

I don't have a manual for 2000 but the reservoir is either under the air filter box or inside the passenger side fender. The check valve is either part of the reservoir or between the reservoir and the intake manifold.