no heat! help plz

[JZA80RR]

my car is a 1990 ma70 turbo

driving around with heater on hot air, suddenly only cold air come out!
if i hit a bump in the road then it can switch back to hot air...

i did put in a new heater control assy and a heater water valve from a friend's car but still the same problem:nono:

have modify the water valve to stay open all the time,but no luck..

its not a bhg and i do not got air in the system!

eny ides ? :1zhelp:

 

[IJ.]

The AC amplifier box is prone to failure and will cause the symptoms decribed as it controls the servo mixer door.

 

[JZA80RR]

where do i find the AC amplifier box ? got a photo of it ?
also if i hit the heater control assy is sometimes go back to hot air:nono:

btw AC radiator and pump is removed from the car..

 

[IJ.]

It's mounted above the glovebox on the dash support bar, the Climate Control is another failure point that will cause your symptom as it sends the signal to the Amplifier. (I've had both fail at different times in the 12 years I've owned mine)

 

[JZA80RR]

do you have the pnc or part number for the Amplifier?

 

[JZA80RR]

nobody now's ?

 

[TurboStreetCar]

When you have no heat check the heater control valve under the hood mounted on the firewall passenger side (USDM At least). Then check it again when you have heat and see if it looks different.

 

[JZA80RR]

got a 2jz engine so the heater control valve is modify to stay in the open (up)position all the time,so i get hot water just not hot air all the time...
heater is cycling between heat/no heat

:1zhelp:

 

[jdub]

Ummm...was this hard to understand? Is it that hard to pull out the TSRM? Is it that difficult to call Jay Marks Toyota?

It's mounted above the glovebox on the dash support bar, the Climate Control is another failure point that will cause your symptom as it sends the signal to the Amplifier. (I've had both fail at different times in the 12 years I've owned mine)