85 C-10 Heater Box questions..

[illmanners]

All,

New to the forum, but not new to rebuilding/restoring..however, do have a few questions that I have not found specifically addressed in any thread relative to heater boxes.

Have an 85-C-10 with A/C and am in the process of replacing the heater core. Have the heater box out of the truck and completely disassembled, new core in place and noticed what appears to be either a broken part, or one that is designed to "flex?" It's on the inner half of the case (the one closest to the firewall.) Have attached a photo showing it in both and upright position and in the "maybe broken" position. If it's supposed to remain upright, I can fix it. If it's supposed to flex (which I can't imagine, as eventually it would break,) I don't fully understand that..

Also, while removing the heater box, I cam across a light pig-tail that I assume is for an instrument that was either not installed in this truck or has been removed by a previous owner..Have attached a picture of it as well. Need help in identifying it. Cigar lighter light maybe??

Last item..does anyone know of a company that makes new sealing rubber or pre-cut weather-stripping to re-seal the inner areas of the heater box and the conditioner box to the firewall inside the engine compartment? I can cut weatherstripping to fit, but would prefer pre-cut.

Thanks in advance and lets; keep these Wide-Bodies on the road..

Illmanners

[MTCK]

Can't help on the heater box. My trucks were all non AC from the factory. That looks like the light that shines at the floor mid dash. Post up some pics of your rig and welcome.

[illmanners]

MTCK,

Thanks for your speedy response and the info on the light. Hopefully someone can answer the question concerning the heater box. I'll get some pics of White Lightening posted soon.

Illmanners

[silverbear]

That tab on your heater box is broken. It is not supposed to move or flex. The other pic is for a bayonet style (1156) bulb. That lamp fixture mounts to the bottom edge of the metal dash between the ashtray and glove box. That way when you open your door the hump area and pedals are illuminated.

[illmanners]

Silver Bear,

Thanks for the info on both the heater box and light as I suspected both but did not want to find out about the heater box problem "after" I had reassembled and reinstalled it so chose to ask those with more experience. I've been members of other forums in the past, depending on what I was restoring, but I think this one seems to have more professional and quick responses. Glad I joined and hopefully, will be able to help other members in the future.

Thanks again,

Illmanners

[illmanners]

Searching the site, but could not find anything pertaining to my "exact" issue. Inherited a project that someone else had started (85 C-10 Step-side,) and have hit a snag. Replacing the heater core and rebuilding the heater box (vehicle has factory a/c.) Ran across what I thought may be a vacuum line coming from the inside of the truck firewall to the engine compartment, but is actually a hard plastic similar to a cable housing and I can't find anything inside the truck to correspond with it..2-pictures enclosed. One for reference of location and the other is a close-up. Any help identifying this lil' bugger would be greatly appreciated.

Best regards to all,

Illmanners

[silverbear]

I think that line is supposed to run to your vacuum accumulator (the plastic ball mounted to the fire wall near the wiper motor). It may run to a "T" prior to the accumulator. My vacuum system on my 86 was hacked up and I am figuring out these same details now. I have also seen on some trucks where the accumulator is mounted near the air box/blower motor. Try searching the threads for vacuum diagrams. I know I have seen them posted in the past.

[illmanners]

Frankie,

Thanks for your response and ideas.

There was originally a tee coming off of the vacuum accumulator, one line coming from it and tee's off under the dash just outside the heater box to operate the door actuator that opens/closes door to switch from heat to a/c..and the other branch of the tee provides vacuum to the transmission vacuum modulator..at least that's the way it was set up when I got the truck. I installed a new crate motor and a TCI Street Rodder Turbo 350 and that vacuum source seems to work fine for the tranny. I'll re-check the vacuum diagrams posted by other members, but my original check didn't reveal much , at least pertaining to this specific issue.

I do want to say that I've been working on vehicles for way too many years, but am enjoying it even more now thanks to retirement and all of the great people on this forum.

Best of luck with your 86 and I'll report any findings that may help others in the future. Likewise, should anyone else have and ideas, that too, would be greatly appreciated as thanks to this forum, none of us are in this alone.

-illmanners in Idaho