guys ,guys, common,you need to check that damn conection wire that flips the door from cold air to hot air inside the cab on the passenger side,left foot area!its VERY common for that little plastic braket to break and it only suck cold air from outside letting you think its your damn heater core,trust me ,been there!!

if its still intact and working properly then proceed to heater flushing!

 

haha, I like the phrase in your sig man

 

Seeing that picture is believing there are 2 cables connected to the lever. A blue one and the other looks black. The cable to my valve is blue, so the black one is the problem. I hear no flap moving when I slide the heater lever. I bet is is not connected to a door/flap.

I have taken the glove box out before and that is easy. I may have hot air this year after all. Now if it would stop raining so I could take a look.

 

x 100 million on this, I replaced the heater core, and some how screwed up all the lever on the climate control, so it wont move and I had to open the flap by hand then hot air all day long. I spent two days wondering why I had cold air with a brand new core, radiator full, and not a damn leak anywhere.

The flap lever is located on the bottom of all that plastic duct work, right by where the vent is for the floor vent on the passenger side.

 

hmm... my trucks have 3 cables... vent control (dash, floor, defrost), temp control, and fresh (in front of windshield) / recirulating (air from in cab).
It's been getting down in the 30's lately, and I get hot air out within 2 miles of driving even with the vent set to 'fresh'.
If it's not getting all that warm, maybe the thermostat isn't working, or the line between the intake and heater core, or heater core to the water pump is partially plugged.

 

How common is it for that water pipe, running along the the exhaust side of the motor to get clogged? I am wondering if I should just check it for the hell of it.

 

Don't know about how common, but imagine it's possible. I mean, if the heater core can clog, why not the pipes that run to and from it?

 

well I beleive the core clogs at the small radiator-like vanes... just a pipe would be a little harder to clog since there's technically nothing for a clog to get ahold of...

but that's just me "get'n all logical" again

 

So I'm in the same boat. My heater never blows anything out that I would consider even "warm", it's kind of like the McDonald's coffee warm. So obviously I'm looking at the heater core, and it's sounds like a biotch to fix but lets simplify in a first thing, second thing, third thing etc. etc. etc..

So, first, Check connection on dash controls for correct flap movement?

Second, check the hoses for clogs?

Third, flush the heater core (or just buy a new one?)?

 

new ones are spendy, but they should last at least 15 years...(not having to do that job again for 15 years is well worth the price)...

i agree w/everyone about the cables, there are a lot (i think i have 3 but i also have A/C_)..
AND i do hear a flap w/the heater.

when i pulled mine, i replaced all the foam with new foam and orange silicon to keep it from ever unglueing itself..b/c i will never go back in there...(its such a pita), now when i open/close them, i hear a soft "thump, "instead of a "clink"...(i used 1"weather stripping

if you don't have A/C it will not be so difficult. and you can leave the blower alone, and just remove the heater..but the dash must come out..

my 1st time took about 12 hours in summer..w/half that laying on my side or back, and the seats removed.

remove the seats..it will save you a lot of aggrivation.
buy new hoses for the core too..

i also "sharpied" the core, and hoses w/year and date for future reference.
also duct taped the ducts b/c they are just snapped together, and i want a solid air vent.

i know im a bit over the top, but i plan on keeping this truck till im 90, and pass it down to the grandkids...(if gas is still around)

btw.
my heat now can melt my shoes..its HOT..and the defrost works on the side windows too.
in fact, i drive w/the sun roof open, and the heat on..in 20 degree weather and snowing, it feels great to have cool air to breath while hot air warms my feet/ bod...(and my freezing G/F stays warm too..thats a miracle)

 

So, undo just the right side of the dash, label everything while you're doing so, and it should be cake?

 

I dunno about "cake", if it's your first rodeo, if ya know what I mean...

 

Well I'm expecting pulling apart the dash...well...to suck...a lot. And there's a lot of crappy wiring in mine from years of adding this CB, that radio, taking those out, putting in another one or two and the automatic stuff that's leftover from the transmission swap, dealing with the A/C stuff, keeping track of it all, finally getting to the core, checking the flap/wires for it, hoses, and if necessary replacing the core itself, then putting it all back together again. I'm thinking it'll take me about 15 hours (first time really pulling off an entire dash).

 

well, I'm one of those "I'm in here, so I might as well replace it" kinda people... if I knew I was going to dig that far into it, I'd have a new core by my side, and I replace it any how, since that's one of those major PITA jobs...

 

A year later, and still no heat for the defroster.









I removed the glove box. I see a black cable that moves when I go from blue to red - the heater contol lever. But I cannot see in there. Too much stuff in the way and my eyes are old.

I have the 1988 FSM but cannot find the heater stuff. Where is the heater diagram in the FSM?

 

try this:

http://www.toyodiy.com/parts/p_U_198...-MRA_8715.html


also can you take a good photo of the water valve under the hood, I need to see how that cable connects to the valve from the controls. I think I messed it up when I took my motor out.

 

In these 2 the cable is disconnected.

 

I have a 1988 pickup v6 Having similar problem. While driving down the road my heater is nice and toasty, come to a light and stop it starts blowing cold air.
And driving down the road my truck is running hot with the heater on.
Also when i start it up in the morning i can hear the water going through the lines and it sounds like something is blocking the water. I also top off my radiator every day cause some how i am losing alot a fluid and its all going into my over flow, kinda like something is blocking it from circulating, maybe thermostat? Any ideas?

 

thatnks for the photos tool. i dont think my calbe is working, gotta figure out how to check things out without having to take the entire dash apart. do you know which direction is open and shut?

 

Here is the loop end of the cable where it connects to the lever for the valve. You can slide the cable off and operate the valve by hand



When the lever is closest to the firewall the valve is open/hot. If you pull the lever towards the radiator then the valve is closed.

The link to the heater parts had a diagram when I first looked at it. I looked at it again today so I could print the diagram, but all that shows up now is the parts list.