[benoit454]

Guys I recently started removing vacuum lines and uneeded emissions junk on the 84 c10. I ran into a couple that gave me questions as to what they go to or work.

They ran off the vac. ports in the thermostat housing, the switch on it had vac. lines that one runs across the intake, valve cover, and up to the firewall, through that sleeve over the brake booster, and back out in the middle right by the sleeve where it connects to this switch or something that has electrical wires on the one side and that vacuum line on the other.

It has the same thing on the other side of the firewall up top had a vac. line going to it and then out the other side is electrical wires, they run down behind the motor and tie in right beside the trans. dipstick, where it's one big switch that has electrical and vac. to it also. then the wires run out and down the back or the motor/bell housing, then over towards the brake booster, and down somewheres.

Now the truck is heat only and th350, not 350c and the trans. HAD the TSC on it, on the pass. side.

Now I unhooked the vac. to electrical switch on the pass. side, that goes down to the big one by the dipstick, unhooked it's vac. line. I also unhooked the vac. lines going to the big thing by the tranny dipstick, and all the ones on the thermostat EXCEPT for the one going to the switch by the brake booster.

Anyone know what they are for? heater? anything important? doesn't seem to have any vac. leaks, but haven't driven it. Only started it and revved it up while listening, seems fine. I can try and get pics if needed.


Thanks for the help. Also I looked in the hayes manual and found nothing at all, there pics were of an a/c truck and didn't have the vac. to electrical things on the firewall.