Stink Ten Two. The second Blazer.

[HO455]

Now the weather has changed I became aware that the heater worked poorly and there was no defroster or vent output. After removing the heater controls and testing them with a hand vacuum pump I determined that the control vacuum switch worked. Further troubleshooting lead me to find the vacuum line from the engine was leaking. When I checked the line at the intake it appeared that it had been plugged with some glue. During the removal of the factory plastic vacuum line it snapped in two. Classic old GM vacuum line failure. Then while I was trying to figure out the way to fix that the line snapped off inside the grommet through the firewall. GRRRR!

After 30 minutes of trying to access the grommet from inside I gave up. There is no way to get at it without removing the heater air box and that meant removing the dash. I wasn't going to dive that deep now. So I found a hole in the firewall near the clutch pedal and ran a new hose from the intake to the switch in the heater control unit.

With a good vacuum supply from the engine now the heater works better and I have a defroster too! Having a non-AC truck it has the lower output blower so airflow is less that the old blue Blazer. I will look into upgrading to an AC blower like I did on my Burban. More is better right?

The only photo I remembered to take is of the grommet where the factory hose went through the firewall.