Boomer

Vent mode on....

So I have a 2004 Grand Prix GT2 that my wife drives.
It used to belong to my parents.

At one point the cabin air filter was changed
(if you have a Grand prix from late 90s to 2005, you know where I'm going with this...if you don't... pay attention)
and the car started to have a water leak in the vehicle.

So I took the cowl apart where the cabin filter is to see the rubber strip thats supposed to divert water around the opening, had fallen into the valley that leads to the drain. This allows water to fall off the windshield directly into where the hvac blower motor is, and eventually into the cabin.
Yes...VERY stupid design.
(now I don't think my father went back to the lubeshop and complained...i would have...whether it was their fault for not putting it back correctly or not)

So I put the rubber strip on, pour water, check for leaks. All is good.
Until Friday.

I'm going to pickup my wife and the blower doesn't work at all!
Take apart the cowl again, sure enough the rubber strip has fallen off.
Check the passanger floor...wet... GREAT!!!

Start doing research and find that this is a VERY common problem and design flaw. Even IF the rubber strip is in place, eventually over time it will fall off and cause water to leak into the cabin causing either the blower fan, blower resistor shortage and possible fire! (keeps getting better and better)
Even some guys who have glued/stuck the rubber in place so it doesn't fall off, have found that water can sometimes leap the rubber if shrinks/moves etc.

So I buy both the fan/resistor and start diagnosing which one is bad or both. And find it was just the blower, resistor is fine (thank god, cause its a female dog to change....)
Stealership wanted 196+tax for oem fan. Aftermarket one was 118 bucks+tax. Resistor was 110+tax as well.
I would have ordered one online if it wasn't such a rush to get the blower working.

So now that the blower works, what about the leak.
Well, seems that GM had a TSB out ( I really wish I read about this back when it happend the first time) and it has a replacement plenum water deflector (Part# 15794785) that fills the entire trench and diverts water into the drain directly. 10 dollars... 10 friggin dollars....

So if you have a grand prix and you don't have a deflector, do yourself a favour and avoid any future swearing and grief.....

Attached are 2 photos.
First is the area where you can see the blower motor and cabin air filter removed. The rubber strip above it is supposed to seal it and divert water around the box.

Second is the plenum water diverter installed. It completely covers that area and funnels water directly into the drain.
10 bucks to fix this

ShowGT

Amazing how something so simple can create something so expensive, $10 was a good investment my friend.

Boomer

only AFTER replacing the 110 dollar blower
hahah

I really wish I knew about the 10 dollar part 2 years ago,
then I wouldn't have had to replace the fan.

On the bright side (knock on wood) the resistor was ok.

Moosetang

Not to be a jerk but the second that car is in that happy spot between failures where it seems like a competent car again, I would trade it in on something else. I don't mean go in debt on something new, but get away from that bomb before it blows again.

Boomer

Don't get me wrong, it's times comin.
But don't let it here that...

Just another point though, the car hasn't costed me a lot to maintain (knock on wood)
Paying 20,000+ for a new vehicle VS keeping a good running car with the odd annoyance to fix for 100 bucks isn't worth the trade yet.
Big ticket items start going, that's a different story.

My annoyance is in the engineering of some of the parts and how stupidly they fail or were overlooked in the beginning or subsequent redo's.
Knowing something is an issue and just not fixing it, later to release a part that does fix it just annoys the **** out of me.
People have been experiencing the same problem in the previous gen, why it was NEVER fixed ...well..that's GM for ya.
Not that Ford is perfect or anything...

Sidenote, I have a friend that has an HHR that had a VERY similar issue.
Costed him a LOT more to fix, and he took it to a shop.
But in the end, the mechanic told him it happens on a LOT of GM vehicles and HAS been an issue for a long time.