Did'nt really. Got it open and everthing inside was sparkly clean. That was a good kind of bummer. Man those nuts were hard to get to.

Checked the lines under the dash that were replaced with the vacuum line. All looks well. Fan is working, for now. Going to the salvage yard Saturday to see if I can hijack one.

I got here late! What are you trying to accomplish?

Trying to create more flow from the fan. It seems to be blowing kinda weak.

Were you looking at the heater core? Because the heater core will not get dirty, the evaporator core (A/C) is the one that gets all plugged up over time and kills your air flow.

You already know this but for other readers...
The inlet side of the evaporator core collects dust, pollen and moisture and over time turns into mold. The mold will eventually grow so heavy that air can no longer flow through the evaporator and results in low air volume from the air ducts.

All GM HVAC (heating, ventalation and air conditioning) systems push the inlet air past the A/C evaporator first and then past the heater core reguardless of the settings of the contols....hot, cold, defrost, vent, heat, floor, ect. It doesn't matter, the air always flows through the evaporator first. This is why the evaporator plugs and the heater core never does....unless your car did not come with A/C and we all know that is unheard of on a Bonneville.

A heater core can plug up internally and prevent engine coolant flow, but not externally to prevent air flow like an evaporator can.

Which way to the thing I need to clean?

I'm pretty sure as soon as you get the blower controller modul lifted out the only thing you see is the evaporator. It is strange that yours was clean though. Mine had a quarter inch of grime.

I thought that was what I was looking at. Youhave to lift the heater unit out and then you see the evap thing. Yep it was real clean.

The core you're after to increase flow (worked well on my car and Jseabert'*, but be careful with wet carpet if you overdo the rinse....see Techinfo for procedure):

Remove the maxifuse relay center cover on the passenger side firewall.
Loosen the relay mounting.
You'll see a small cover with a resistor pack on it (if I recall). Remove this.
Look down in the hole. See it?

My flow increased 25% on the SSEi. Haven't done it to Boost2 yet.

Here'* a couple of inside pics to help you with your task.

This is the 97 donor car after the evap cover was removed. Note the gathering of pine needles in the corner. IMO this isn't enough crud to cause a problem but more certainly could be.


this is what I found in my 90. it appears to be a rodent nest: This ammount of crud is sufficient to limit airflow some.


Note: pics are for illustration. It'* not necessary to remove the evap covers to clean. Access through the BCM opening. It'* a huge job anyway if the motor is still in.