Question about 2003 Chevrolet S-10

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2003 S10 heater controls dont work / work with most heat comong through front vents replaced vac cannister, vac lines from transfer case to heater control switch on transfer case and one actuating motor under the dash the whole system is right a 16 pounds right where it is supposed to be heat works but i have to close the front vents for to get def and even then there is heavy heat coming through the front vents and even bought a heater control from yhe bnre yard with no change any ideas

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  • Anonymous Mar 23, 2014

    i have heat in the back controls but my fan does not work in front.



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Your Blend / mode door inside the heater ac blower box. is stuck or not moving completly into place.

Posted on Oct 17, 2009


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2003 chevy blazer heat won't blow on floor

Transfer case switch may be bad allowing trans fluid in vac. Lines and can reach as far as heater switch common problem fix these all the time 17 bucks for tranfer case switch and 20 foot of vacume hose and replace all the vac. Hose because this issue causes pcv to not work correctly so the moisture from crank case ends up going out the distributor vents causing cap and rotor corrosion there is service bulletin to remove distributor vent screens i would fix that since you will be working next to it any way

Dec 02, 2013 | 2003 Chevrolet Blazer

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94 S10 Blazer, 4X4 , has a high low rocker switch, which i hate, it wont engage in 4wd mode, how does that stupid switch work ?, Vaccum ?

You will probably need a shop manual to work on it yourself. The switch on the dash controls a vac servo on the transfer case. The servo controls an actuator under the battery which sends vac to the front axle. The transfer case and front axle servo work together.

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02 mountaineer no vacuum at heater control valve

You are correct. That is the common cause of no heat if the water pump and therm are still good. The plastic door is most likely stripped.

Oct 14, 2012 | 2003 Mercury Mountaineer

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I have a 2002 s10 4wd will not work

You would need to figure out if the transfer case is working.
It should have a two speed transfer case which is controlled electrically, and a vac switch for the front differential.
If the transfer case turns the driveshaft to the front dif it could be the vac control.

Sep 08, 2012 | 2002 Chevrolet S-10

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I have a 96 gmc jimmy i have changed the actuator,actuator cable,all the vac lines,vac switch and switch on differential and still the front tires dont engage,the transfer case is locking in and so is the...

on your Jimmy you need to put it in 4 hi and up under the battery tray is the actuator for the front dif. make sure the vac hose going up to it has vacuum. if it doesn't then start tracking the hoses going down to the transfer case. one goes to the actuator, one to the vents on the transfer case and transmission and one goes back up to the vacuum canister, it's located on the hood on the drivers side. if the canister isn't getting vacuum then nothing is going to work. i just had to repair the hoses in the truck i put the trans in. the 4 wheel drive now works in it. i would have never know this, the hoses drop over by the exhaust and get hot and burnt and start cracking and breaking up and leaking. this can also cause some minor running problems. also. one last note. where the hoses attach on the transfer case. that connector has to go on correctly. it has a pin hole in it to line up on. if you put in on wrong things won't work.

Apr 22, 2012 | 1996 GMC Jimmy

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When the air conditioner is working cold air only comes out of heating vents

Check your vac. lines, you probably have a broken vac. line under the hood which feeds the interior heating controls. When vac. is lost it goes to heater vents.

Jul 15, 2010 | 1995 Pontiac Trans Sport

1 Answer

2004 ford fx4recently i dropped off in a rut on frontandwhen i engaged 4 wheel drive i heard a racheting four wheel drive now.mechanic told me it was cv joint but i dont understand how a little...

Sounds like the IWE ( Integrated Wheel End ) did not lock in for some reason.

Could be the IWE solenoid did not shut off the vacuum to the wheel ( usually the solenoid problem is the other way around ).

Could be the vent tube from the IWE into the engine compartment is plugged.

Also could be a problem with the transfer case.

Is the system ESOF ( Electronic Shift On the Fly ) or MSOF ( Mechanical Shift On the Fly ) ?

Operationally vacuum holds the IWE ( Integrated Wheel Ends ) out, and once vac is removed the spring engages the IWE.

Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
If it turns it is a problem with the transfer case.
If it doesn't it is a front axle engagement problem.

- If the front drive shaft does not turn :
Shut of the truck ( still jacked up, and supported ) remove the vac lines from the IWE. The spring should push the gears in, without the vac line on.
Check the vent line ( tube that is routed into the engine compartment with nothing attached to it ), for blockages.
If the vent line is clear, and with the vac lines off the IWE should be engaged ( both front wheels locked ).
If they lock, the problem is with the IWE solenoid not shutting off vacuum to the IWEs. There is a TSB on the 2004-2006 IWE solenoids, a newer revision has been made, and used from 2007 and newer MYs.

Here is a block diagram of the IWE system

Start with the lifting and supporting the front of the truck to check the front drive shaft when 4H or 4L is engaged to know which way to look.

Some times the connector on the transfer case for the ESOF version can be corroded and just needs to be cleaned.

Jun 23, 2010 | 2004 Ford F150

2 Answers

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The lines connect to the toggle switch, and run down to the transfer case.

Feb 03, 2010 | 1985 Dodge Ramcharger

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The heater control does not change the air flow to any one position, all vents seem to be open at one time.All the fans ,air & heat work, but the air flows from all vents on this 2003 s10 pickup.

Check any vacuum hoses from engine all the way to heater/a/c housing under dash,for leaks. Then manually move or put a vacuum guage on every vac motor you can see and get to. Your working your way back to the switch. If you want to you could start at the switch but % wise and degree of difficult your better to back in. Now a schematic will make the process easier. Hard to work on a system you don't know .Electrical or Computer sometimes play into these, I have an older S10 so no computer.

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My 2003 s10 won't take fuel. when pumping gas it burps it back up, goes in real slow. name is Keith..and your fuel pipe to your fuel tank has a vent tube..and its either stopped up by a mud dobber or the line is pinched off or crushed..but the problem lie in ya filler neck..i hope this has helped..if not..please write me back

Jun 29, 2009 | 2003 Chevrolet S-10

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