Next up remove the Heater Box - Seeking education

[71CHEVYSHORTBED402]

71 C-10 tear down - all new to me


1. Wire harnesses & receptacle: Can you describe each of the two plugs mounted onto the RH side of the heater box? What are they called, and what's the receptacle unit called? Edit: It's the Blower Relay.

2. Heater core hoses (5/8" inlet, 3/4" outlet). I'd like to keep this running as long as possible. There's a lot of confusing information for bypassing "the" heater core. If I plug the ends of each hose, does that create a recirculating concern? Suggestions? It's only temporary, and the truck doesn't even leave the driveway.

3. Why do I see two heater cores......WTH? Edit: Ah, Evaporator Core....Yeah, I'm pretty green.

4. Other than good notes, pictures and the obvious, (I won't reassemble this for two years plus),any suggestions for removal? Should I remove the evaporator core assembly before the heater box?

Thanks for any advise.

[71CHEVYSHORTBED402]

Grasshopper looking for education. I discovered my "second heater core" (ha!) is an evaporator core. Should I remove the evap. core assembly before removing the heater box?

[kehstr]

is this an ac or non-ac cab, can't quite tell by your picture.

[71CHEVYSHORTBED402]

Originally Posted by kehstr

is this an ac or non-ac cab, can't quite tell by your picture.

Sorry for the bad photo. A single run (taped-up) has two plugs and a ground wire. Both plug into a unit mounted to the RH side of the heater box. The front (i.e., closest firewall) plug is four wire, and the rear plug is one wire. Then a screw for the ground. It is A/C.

I'll see about a better image............I replaced the old with one more better.

Edit: It's the Blower Relay.

[kehstr]

if you ever plan on starting the truck i wouldn't cap the heater lines, just buy a 3/4 to 5/8 adapter, they are pretty cheap at most hardware of auto part stores. that will still let coolant flow through everything.
If you plan on taking the evaporator box off, i would pull that off first, so you can see how things come off, so you kind of have some ideas to how it will come apart. The evaporator box comes off pretty easy, with about 3 nuts, and about 5 bolts. The foamy rubbery stuff that seals the box to the cab, and the inside header box to together is really cheap, you can pick up a complete kit for $25 from lmc, and find it cheaper anywhere else. so don't be too worried if you ruin them.
hope that helps

[71CHEVYSHORTBED402]

Originally Posted by kehstr

if you ever plan on starting the truck i wouldn't cap the heater lines, just buy a 3/4 to 5/8 adapter, they are pretty cheap at most hardware of auto part stores. that will still let coolant flow through everything.
If you plan on taking the evaporator box off, i would pull that off first, so you can see how things come off, so you kind of have some ideas to how it will come apart. The evaporator box comes off pretty easy, with about 3 nuts, and about 5 bolts. The foamy rubbery stuff that seals the box to the cab, and the inside header box to together is really cheap, you can pick up a complete kit for $25 from lmc, and find it cheaper anywhere else. so don't be too worried if you ruin them.
hope that helps

Helps ALOT, thank you. Yes, everything needs to come off. Seems I've bypassed the heater core before, just as you've suggested.