Unknown parts

[kmanrsss]

Im in the process of swapping an 83 cab onto an 87 chassis. I pulled and labeled as much of the harness as I could but there were things that weren't hooked to anything and I was looking for some help. The first is a piece of 3/8ish heater/vac hose that passes though the firewall next to the fuse block and runs to a switch similar to a brake light switch, right behind the brake light switch. It has a 3/8 Bol in it on the engine compartment side.

The 2nd so far is a 2.5inx4in black box with about 18in of pigtail to a 3 wire connector. Wires are blk/wht. Brown/wht. Red/blk. The box has a hinged cover on one end with a printed circuit board. This wasn't hooked to anything. It was mounted under the dash just to the right of the steering column. I will get some pics up later if needed. Thanks

[Captkaos]

The hose is the Cruise control hookup, the box sounds like the controller for it.

Look at the picture here:
http://forum.73-87chevytrucks.com/smforum/index.php/topic,12120.msg201240.html#msg201240

[kmanrsss]

yup that's the cruise hose, but the box isn't for the cc i don't think, unless there's 2 control boxes.  hopefully pic 1 shows this. Next question is hopefully pic 2, purple wire and a pink/blk stripe. it wasn't labeled so i either missed it or it was disconnected before i started the swap. it comes out of the harness with the radio wires.  thanks again for the help

[Sartobuilt]

That plug is the electrical part of the Cruise control vacuum switch.

[bd]

...hopefully pic 1 shows this. Next question is hopefully pic 2, purple wire and a pink/blk stripe. it wasn't labeled so i either missed it or it was disconnected before i started the swap. it comes out of the harness with the radio wires.  thanks again for the help

Pic #1 may be the fuel module used with BB TBI engines.
Pic #2 is the connector that attaches to the brake switch for the CC, like Sartobuilt posted.

[Captkaos]

What is written on the box in pic #1?  There should be a PN, is this a 1/2T truck?

[kmanrsss]

There are 2 numbers.  1st is 7076, 2nd is 10052955. It's a 3/4 ton

[bd]

...number... is 10052955.  It's a 3/4 ton

That P/N changes to ACDelco 10052973.  It's the Fuel Pump Control Module.

[kmanrsss]

Interesting. I'm pretty confidant that I didn't unplug it as its not labeled. Is it possible that's why only 1 tank worked? Where should it plug into? Thanks

[bd]

Typically there's a mating plug left of the column, up behind the cluster.  That module should have no effect on the individual tanks - it overrides the ECM and should only affect the duration of time the fuel pump relay is energized after the ignition is switched OFF.  Typically, it's used only in big block applications.  See the wiring diagram here... http://forum.73-87chevytrucks.com/smforum/index.php/topic,9072.msg198713.html#msg198713

[kmanrsss]

So spare prts as I don't have a bbc? I also haven't found an unoccupied plug that it would go to.

[bd]

Previously, I posted it's generally only used on BB applications - I should have added, it's also used with 5.7L engines in chassis greater than 8500 GVWR. 

[kmanrsss]

Thank you BD, I guess I missed that part of your previous post.

[bd]

You didn't miss anything.  My explanation was incomplete.