Hi All,
I am new to this forum but need help with my Blazer.

I have a 2000 Blazer that the heater blows continuous hot air.
The faster the truck goes the harder and hotter the heater blows...
The air conditioning does not appear to be working properly also.

Any help, suggestions or advice greatly accepted
Thanks in advance

 

well I am not sure on the blazer, but on my nissan I had a similar problem and it was a vacuum line was cracked, If the heater controls on the blazer are vacuum actuated that could be your problem also.

 

Air is always flowing over the A/C core, but should not be always flowing through the heater core. The responsibility for channeling air for temperature control is on the temperature actuator which is fully electronic control. It sounds like this is the source of the problem in terms of the heat all the time issue.

With the A/C not coming on, that is likely a problem with the charge level. You can manually engage the compressor by installing a fused jumper wire across the A/C relay in the underhood fuse/relay center. If it still does not deliver cold air (after fixing the temp actuator problem), then your charge is probably low.

I am not sure what is available in New Zealand, but here in the US, you can pick up a relatively inexpensive recharge kit and manually engage the compressor again to pull the refrigerant in.

If after checking the charge level, the compressor still does not kick on, then you have to determine if it is a problem with the low pressure switch (on the big silver can on the passenger side - somewhat common problem) or the high pressure switch (back of the compressor).

 

Thanks mate
i will get back how i get on

 

Wow! another Kiwi! Welcome mate.
Post up in the New Members area & introduce yourself (& your truck).

If you become a regular we'll be 3! LOL Where in the City of Sails are you?

I currently have pretty much the same problem. I've had hot air blowing weather the a/c is on or not. Turns out a gear in the blend door motor thing that switches the a/c from hot to cold is busted. Problem of course is Bunce are the only guys in town who keep parts but, none in stock at the moment. A new unit costs $198.

See my post in this section titled "Air conditioner".

 

Which requires removing the WHOLE dashboard assembly to gain access to.

Here is an alternative method to gain access to the blend door, BUT it only pretains to NON-GM products (currently). This method involves cutting into the heater plenum, replacing the motor-gear assembly and patching up the hole.

Check it out. -->> http://www.heatertreater.net/

 

Don't believe everything you read on other sites... Especially when it has nothing that really applies to our trucks.

I have yet to see or hear of anyone breaking the blend door. The far more typical failure mode is the plastic gear inside the blend door actuator that fails. And, as other threads on this forum can attest to, the actuator can be replaced without pulling the dash if your hands are small enough or you are otherwise creative in your tool selection.