lordfury007 wrote:
Just been looking under the dash trying to work out the air vent system in my sierra, since i've bought it, it hasn't really worked properly (ie: air doesnt go where you tell it to go)... and i've found out the last owner didn't bother connecting half the pipes or cables together, so the whole thing is a jigsaw...
I was thinking of just ripping the whole thing out, and installing something custom - all it really needs is a few 12V fans, a little trunking and a few switches and cabling
anyone done it or know of a better way?
and how do you wire it so it turns off with the ignition?
Do yourself a favour and stick with the stock setup. When it works it works well.
Connecting the pipes is all pretty straight forward, you have a manifold that connects the middle 2 vents in the dash into the top of the airbox/blower assembly. Then you have 2 moulded tubes with a convoluted body that run to the vents at either end of the dash. That's it for the vents!
I can't remember exactly where the connectors are but there should be one that goes to the body of the blower assy. and the fan switch goes into the loom that runs along behind the dash itself. The fan should have power when the ignition is on, but not when accessories is on.
The control cables seem a little tricky, and you're probably better off looking at one that's already set up. The hot/cold one is easy, it goes to the heater tap on the firewall. The vent one goes to a little arm on the side of the airbox, same goes for the recirc/fresh cable. Finding these isn't a big issue, but getting the routing of the cables is probably more difficult, as I said you'll probably want to look at one that's setup already.
ALSO don't panic if you switch to heat and dont get hot air from the vents, hot air only comes out the bottom of the heater box, and to the windscreen demister.