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No Heat, No A/C. Fan speed switch IS working

Discussion in '2nd Gen. Tacomas (2005-2015)' started by falbradawg, Jan 11, 2012.

  1. Jan 11, 2012 at 8:05 AM
    #1
    falbradawg

    falbradawg [OP] Member

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    I have been following this post http://www.tacomaworld.com/forum/2nd-gen-tacomas/70275-fan-speed-switch-not-working.html


    And with the help of one of the forum members he enlighned me that my problem is different. MY fan works! But, I have had no heat and no A/C (since last Aug 2011).

    My air blows great (from the fan), but does not get hot or cold. (Well it is cold now because of outside temp!)

    My problem started in Aug 2011 and the a/c only worked (was cold) on fan high. Then I would have to close all of the vents except the one next to the driver to get any cold air at all. (When A/C was on you could hear a hiss behind the dash) Then it just stopped getting cold. Again, the fan blew (all speeds work) fine. Just not the right temp would come out.

    Fall started and the heat worked maybe 3 or 4 times and now not at all.


    “Melsman” mentioned that it could be “like something is affecting the airflow over both the heater core and the A/C evaporator core.”


    I am TOTALLY lost and it is getting COLD to drive to work! (even in Memphis)

    (Forgive me I was a Corpsman in the Navy and NOT mechanically inclined!)

    Btw my cousin is a Toyota mechanic and he says has never seen this problem...... thank you!! He did mention


    Many thanks to “Melsman” for the advice on this to start this thread!
     
  2. Jan 11, 2012 at 8:29 AM
    #2
    nhtundra

    nhtundra Well-Known Member

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  3. Jan 11, 2012 at 10:07 AM
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    BlueT

    BlueT Well-Known Member

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    Most likely is that electronic Mode switch (servo) or airmix servo> More likely its first thing. Toyota followed the dumb idea of other car manufactures to use Potentiometer in order to control settings instead old fashion wire. You need to run checks which are outlined here

    http://www.ncttora.com/fsm/05+/data/ileaf/06toyrm/06toypdf/06rmsrc/rm2006ta/04600910.pdf
    and here
    http://www.ncttora.com/fsm/05+/data/ileaf/06toyrm/06toypdf/06rmsrc/rm2006ta/04601410.pdf

    Ask your cousin to help you. On the other hand its strange he did not hear about this :D
     
  4. Jan 11, 2012 at 10:58 AM
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    falbradawg

    falbradawg [OP] Member

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    Thanks! I had found the repair manual before but had no idea where to start!

    THanks for the advice on the mode switch! I just don't want to have to take it to the Stealership! THANKS!

    BTW, my cousin lives in Atlanta, I am in Memphis! :)
     
  5. Jan 11, 2012 at 11:54 AM
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    MountainEarth

    MountainEarth Well-Known Member

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  6. Jan 12, 2012 at 3:24 PM
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    falbradawg

    falbradawg [OP] Member

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    Ok, I bought a Haynes Manual and can't find anywhere in the book a "electronic Mode switch (servo) or airmix servo." I also did a google search and can't even find one if I needed to replace it. Thoughts???
     
  7. Jan 12, 2012 at 5:09 PM
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    falbradawg

    falbradawg [OP] Member

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    Another update..... Checked both heater hoses going into firewall after driving several miles and BOTH hoses were cold.
     
  8. Jan 13, 2012 at 6:44 AM
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    falbradawg

    falbradawg [OP] Member

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    SO after driving to work this morning both hoses are still cold. Haynes manual says it could be an obstruction. So when I get home I will try to flush them. Haynes sayd if that does not work I need to replace the heater core.........BUT.....

    My A/C does not work either (since August) so I am thinking that something bigger may be going on.

    HELP PLEASE!!!
     
  9. Jan 13, 2012 at 7:13 AM
    #9
    skytower

    skytower Well-Known Member

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    Hitch and wiring, aux back-up light, rear strobe lights, radio and underseat sub.
    If both hoses are cold, your coolant is probably low, or your thermostat is stuck open. Either will cause this. IIRC there is no cutoff valve for the heater core on our trucks. This assumes that your engine is at operating temp/midscale on the temp gauge.
     
  10. Jan 13, 2012 at 7:48 AM
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    falbradawg

    falbradawg [OP] Member

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    The engine temp has been working at normal temp since all of this began....could it STILL be the termostat? Would low coolant cause the heater not to work?

    THIS is why I work on old VWs!! None of this crap to worry about! :)
     
  11. Jan 13, 2012 at 9:32 AM
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    skytower

    skytower Well-Known Member

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    Hitch and wiring, aux back-up light, rear strobe lights, radio and underseat sub.
    Low coolant will cause insufficient flow to the heater core in most vehicles. If coolant is full in radiator and overflow, I suspect the heater core is plugged. If it were flowing properly, the lines would be hot. If the lines are hot, then you suspect the blend door controls.
    Remove the lines from the heater core and blow low pressure air through. No air=clog.
     
  12. Jan 13, 2012 at 9:44 AM
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    skytower

    skytower Well-Known Member

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    Hitch and wiring, aux back-up light, rear strobe lights, radio and underseat sub.
    Note:
    The water pump circulates fluid through the heater core independant of the thermostat. As long as the engine is running there should be flow. The thermostat only controls flow/temp of fluid through the radiator.

    The only time the thermostat affects heating is when it is stuck open.
     
  13. Jan 13, 2012 at 10:30 AM
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    falbradawg

    falbradawg [OP] Member

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    I had a Navy (Engineman) look at it during lunch here on base. (I am in the Medical field).

    There was hardley any coolant in the overflow bucket.

    The A/C clutch did not engage when I turned on the A/C.

    There is a hose that comes from the radiator (pass the battery) to the side (where the A/C clutch) is located. He said it has oil stuck to it which makes him believe that the hose leaks.
     
  14. Jan 13, 2012 at 12:35 PM
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    skytower

    skytower Well-Known Member

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    Hitch and wiring, aux back-up light, rear strobe lights, radio and underseat sub.
    Start looking for coolant leaks. Water pump and heater core are the most likely suspects, followed by the radiator and head gasket. Look for pink crust right under the water pump. If you find no leaks at the water pump, pressure test the coolant system, then exhaust gas test the coolant system if you find a leak. Exhaust in coolant=internal engine coolant leak. No exhaust=heater core, radiator, hose.

    The AC system is a little more in depth to test and requires special test equipment. A refrigerant sniffer will tell you if you have a leak in the evaporator. Dye and an infrared light will tell you if you have a hose, compressor, connection, or evaporator leak, but that requires some r-134a in the system. A vac test will tell you very quickly if you have a leak, but will not tell you where.

    Whatever you do, DO NOT use a sealant to fix the AC leak. No one will work on your AC system after that. It screws up their equipment.
     
  15. Jan 17, 2012 at 11:52 AM
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    falbradawg

    falbradawg [OP] Member

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    UPDATE!!!

    I have been fighting with myself all weekend to get the courage to post this....

    It is AMAZING what a little Prestone added to your radiator will do for your heat! Yes, my heat works now! :)

    BUT, My A/C is still jacked up, so all of your help here helped me diagnose that problem. When it gets warmer I will work on that.

    Thanks everyone!
     
  16. Jan 17, 2012 at 1:46 PM
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    skytower

    skytower Well-Known Member

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    Hitch and wiring, aux back-up light, rear strobe lights, radio and underseat sub.
    Been there, done that. The things that stick in my mind the best are the ones that I screwed up the worst.

    AC makes the defroster work. It cycles when the selector is in the Front Windsheild Defrost mode. It would be a really good idea to fix it before the summer. Eventually the compressor will fail without r134a in the system. That is, if it is cycling at all.
     
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