Brief write up about removing dash/heater box

[someotherguy]

It's a big job to pull the dash, but I really had to. The main harness got damaged somehow...maybe mice. I think you could replace the heater core and evap core without removing the heater box. Once I had the dash out though, it seemed easier to pull the box out to change the cores. The box had a mouse nest and smells like pee so I will be able to clean the box with some bleach water too.

Heater core yes, it's designed to be replaceable without pulling the dash. There's a couple screws that are tricky to get to but it's possible.

Replace the evaporator core? Pull the dash and box.

Richard

 

[Yamaben]

Heater core yes,
Replace the evaporator core? Pull the dash and box.

Richard

I imagine 90% of these trucks have mouse pee in them too. They need taken apart and cleaned anyway after 30 years

 

[nakashimanoyoto]

If you pull out the carpet and heating pad you can get the second section of the evap box out. Hardest part is getting the two bolts near the transmission hump. With a long bit and 90 degree bit driver you can use a mirror and light to spot those little buggers and undo them. Undo the evap lines and unscrew the bolts that mount the evap unit to the firewall and you will have enough room to drop the second section which will give you access to wiggle the evap out. I would vacuum out everything while it is apart. Hardest part of the reinstall is getting second section back around the front of the new evap unit. But it's nice having a complete leak free AC system.

 

[someotherguy]

If you pull out the carpet and heating pad you can get the second section of the evap box out. Hardest part is getting the two bolts near the transmission hump. With a long bit and 90 degree bit driver you can use a mirror and light to spot those little buggers and undo them. Undo the evap lines and unscrew the bolts that mount the evap unit to the firewall and you will have enough room to drop the second section which will give you access to wiggle the evap out. I would vacuum out everything while it is apart. Hardest part of the reinstall is getting second section back around the front of the new evap unit. But it's nice having a complete leak free AC system.

Sounds like an absolute pain; if it's on an 88-94 I'd just as soon pull the dash as it's not that bad of a job. 95-up is another story. It's only a little bit more work but that little bit would have me weighing my options. Of course the increased brittleness of the 88-94 plastic all these years later would also have me flipping a coin on the dash pull.

Richard