97 S-10 Blazer A/C Help

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  #1  
Old 08-05-06, 01:58 PM
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97 S-10 Blazer A/C Help

The A/C on my 97 Blazer stopped blowing about a week ago. After a little research, I replaced the blower motor resistor, hoping that would solve the problem. It did, but only for about 5 minutes. Next, I replaced the blower motor and installed another new resistor (in case the other had gone bad). My A/C worked for about 10 minutes, but didn't work the next morning when I started it up. I suspect it may be a short but am not sure what to do next. I am not very experienced with auto repair but cannot afford to take it anywhere at this time. Any help is greatly appreciated. If I should begin to check for a short, how should I go about doing that.
 
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  #2  
Old 08-05-06, 07:37 PM
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Originally Posted by tmoniz76
Any help is greatly appreciated. If I should begin to check for a short, how should I go about doing that.
If you don't have a Chilton's manual for your truck, you could try either buying one or borrowing one from the local public library. I prefer the "Total Care" manuals personally, they are generally more detailed. These manuals have wiring diagrams that could help you. Your library might actually have actual Chevrolet or GMC manuals you could refer too.

I didn't see wether or not you replaced any fuses? Generally if there is a short, they are the first to go. Since you replaced the blower fan and resistor with new ones and had the same problem, I'd start by checking all the power connections to the blower for overall condition. You could have a open or a short in the circuit. If you have access to a DVM you could probe the blower motor leads while the system is on to see if there is power to the motor. It's not hard work, just time consuming because you have to trace the wiring all the way back till you find the problem.

Christopher
 
  #3  
Old 08-05-06, 10:07 PM
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If the blower still works on high, the resistor is probably blown again. You can test it if you have an ohm meter or battery operated test light. You'll need to check for continuity on the leads on the thermal limiter, an oblong shaped part on the resistor assembly with 2 leads coming out of it.
If it doesn't work on the highest speed, you could have a bad fan relay.

Not sure if you did this, but anytime you replace the resistor make sure you install it back into the housing where it came from before turning on the blower or you'll overheat and ruin it. It needs the air from the blower to cool it.

The next time you get it running again, run the blower on high speed only for at least an hour or so to determine if everything works well without the resistor being a factor.
 
  #4  
Old 08-06-06, 04:31 AM
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Originally Posted by tmoniz76
The A/C on my 97 Blazer stopped blowing about a week ago. After a little research, I replaced the blower motor resistor, hoping that would solve the problem. It did, but only for about 5 minutes. Next, I replaced the blower motor and installed another new resistor (in case the other had gone bad). My A/C worked for about 10 minutes, but didn't work the next morning when I started it up. I suspect it may be a short but am not sure what to do next. I am not very experienced with auto repair but cannot afford to take it anywhere at this time. Any help is greatly appreciated. If I should begin to check for a short, how should I go about doing that.
tm,
I had the same problem on a Mercury Grand Marquis. The blower motor was okay.......On mine the blower resistor pack and the speed selector switch (on the dash) were both bad.

The switch was a no-brainer because I could physically see the damage. It looked like it had been on fire.
After replacing both items, I never had a blower problem again!

I notice you didnít mention the speed selector switch; maybe its worth looking at?
Good luck,
Phil
 
  #5  
Old 08-06-06, 09:51 AM
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The A/C went from working fine at all speeds to not working on any. I did check the fuses and also looked at the switch before doing anything to the resitor/motor. The thing that seems odd to me is that after replacing the blower motor and resistor, it worked for a little while until I started the car the next day. I suppose I'll start checking from the blower motor connector and work my way back. Does that seem like the best path to take? Thanks for all of the help.
 
  #6  
Old 08-06-06, 10:32 AM
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Originally Posted by tmoniz76
The A/C on my 97 Blazer stopped blowing about a week ago. After a little research, I replaced the blower motor resistor, hoping that would solve the problem. It did, but only for about 5 minutes. Next, I replaced the blower motor and installed another new resistor (in case the other had gone bad). My A/C worked for about 10 minutes, but didn't work the next morning when I started it up. I suspect it may be a short but am not sure what to do next. I am not very experienced with auto repair but cannot afford to take it anywhere at this time. Any help is greatly appreciated. If I should begin to check for a short, how should I go about doing that.
tm,
When you say the A/C isn't working, do you mean just the blower motor or the A/C refrigerant part of the system?

If the blower is not moving air across the evaporator, it might appear the A/C isn't working because the evap will cool down so fast it'll cycle the compressor off on low pressure.

Try running the A/C on normal (not Max) and take the car for a drive. Running the A/C on normal brings in outdoor air over the evaporator. With the car moving you'll get a little more air flow than on MAX A/C W/no fan; that and the hot outside air should put enough of a load on the system to keep the compressor on long enough for you to feel a little cold air coming out of the vents.

Most people who don't understand A/C think that MAX A/C makes the air colder by engaging the compressor to run continuously. In fact, Max A/C will make the compressor cycle more because it puts the air flow in "recirculation" mode. Basically, you're cooling air that's already been cooled. When this happens, there's less of a load on the system, which in turn causes the compressor to run less.
Phil
 
  #7  
Old 08-06-06, 07:04 PM
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OK, I believe it is just the blower that is not working. I did what you suggested, Phil, and turned the A/C to normal and did get some cold air through the vents when the vehicle was in motion. Does this help to pinpoint the problem? I really do not understand alot about cars. The only repairs I've done have been with the help of a manual. I currently possess a Haynes for the Blazer, and it offers no further suggestions.
 
  #8  
Old 08-06-06, 07:40 PM
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Originally Posted by tmoniz76
OK, I believe it is just the blower that is not working.
tmoniz,
Since you replaced the resistor pack twice and the blower motor too, I'm kinda' leaning towards the fan speed selector switch.

If you're good at electrical troubleshooting you could bench test the motor to make sure it's still good. The resistor pack can be checked with an ohm meter as well as the speed selector switch.

It's kinda' difficult to tell you how to do it.....Maybe you should price out the switch and if it's not too expensive, go ahead and replace it!
Good luck,
Phil
 
  #9  
Old 08-08-06, 08:42 PM
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Smile

Finally solved the problem... the blower motor relay was burnt up. I don't know alot about cars (as you can tell), and I rely on a Haynes manual for repairs. It doesn't even mention that there is a blower motor relay, and it's an easy fix. From now on I'll be getting the Chilton's total care as Chris T suggested. A friend of a friend helped me out and also mentioned that the blower was probably faulty and caused this to happen as well as burn up the resistor. Thank you so much for all of the replies, you guys are great and provide a great service to alot of people.
 
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