Fan stopped working on high setting..

[96tsport]

Boss came home & said the fan quit but what air was coming out seemed to be blowing cold..

Had a quick look & the fan worked on the first 3 settings but not on high.

Hmmmm..

Lucky for me ..nothing serious, otherwise ..boss gets like this ->

[inafogg]

YEA SOUNDS LIKE BLOWER RESISTOR.lots of info here if you do a search

[LMP]

Resistor not used with high speed. Check high speed relay and socket, a common problem specially with those using the high speed setting for long periods. On high, this is 25 amps pulled through wires and relay contacts...a little more than the design value of those components, it seems.
www.avigex.ca/xport/heaterrelay.jpg
www.avigex.ca/xport/hvac_diagram_front.jpg

[brcidd]

depending on the year- it couild be the circuit breaker as well- swap it with the one for the power seat-be careful they can get really hot- if car has been driven lately- on left side of dash is the breaker box...

[96tsport]

Only had a chance to do a quick google ..so far. Found this thread interesting (quotes below) as it talks about a worn out blower motor ..blowing resistors.

Probably mine is original & was gonna get around to changing it, the main problem being in winter when at low setting, where normally you don't even know (or barely hear) the motor is running, instead there is a constant audible chirping (for lack of a better word) sound that goes away at higher setting..

Read about a fix (years ago..) involving drilling a small hole at the back of the motor & getting some grease in the bushings (bearings?).

Read a thread here where there are 2 types of blowers & that one is not right (or doesn't work ..fit) ..or something.

If the resistor is blown, there is probably a good reason. You should also check the blower itself so you dont end up changing the resistor again in a few days/weeks when it blows out again because the blower motor is starting to go bad. My 93 had some noise in the blower bearings for a while when "I didnt have time" to change it.. finally my resistors burned out for the lower settings and I ended up changing everything and everything worked great then. My dad went through 3 sets of resistors before finally changing the blower motor like I told him to do the first time

Mike is right and wrong. A bad blower will take out a resistor but resistor replacement especially the original on a 2000 is common. Gm used to use a card (very thin) with resitances built in to control blower speed they overheated easily and died. In the last couple of years we have gone to a much beefier type of resistor that dissapates heat much better. Go GM only on the replacement and if your resistor goes bad in xx time not sure how long probably a year you get a new one for free then buy the motor.

I have manual seats so can't swap that circuit breaker.

BTW brcidd ..also have a 88 gm 3500 rat powered dually ..~245 clicks total now but with a fresh motor at ~ 217 thou..

[LMP]

..in case you did not notice: (see links in post above)
- there are no breaker nor fuses in the high speed circuit: just fusible link H that, if blown out, would kill a lot of other things too and alternator would not charge
- there is no resistor in the path of the high speed circuit: just the high speed relay.

[96tsport]

Originally Posted by LMP

..in case you did not notice: (see links in post above)

Hmmm ..missed the point of your post (half asleep ..work nights..) when I had a look at the thread yesterday. Looks like it's right on the money.

Turns out there's a Partsource store around the block from where I live that I just started to check out. My understanding is they're part of Canadian Tire & I like what I see so far. They have the relay in stock for ~ 40 bucks, fan motor for ~ 60 & with the fan ~ 100.

Ended up grabbing a set of cheap front pads for ~ 20 bucks (good ones were ~80). Had them replaced last year but..wrench said they wear out quick compared to the backs. He said he put in fresh shoes in the back a few years ago for certification with purchase & when I asked him to have a look .. said they last forever.. but I'll have a look at those too.

Haven't done much of my own maintenance in years.. but getting back into it again now. 2 of my kids just got their liscences just recently (learned to drive in the Tsport) & want the vehicles in tip top shape. I've had ~ 4 partial brake failures ..over the years, 3 were brake lines & the last one ..a rear wheel cyl let loose ...pedal went almost to the floor but the fronts still worked. When the shoes were replaced ..wheel cyl was bone dry.. Had one (wheel cyl) with a slow leak ..in the past, but never one that just suddenly blew..

Have a few dodge minivans & doing some extensive brake work on those right now including rolling my own brake lines.

[96tsport]

Bingo! The #80 & 37 pins were visibly burnt (& plastic melted) at their bases, where they meet (& go thru) the plastic of the relay casing.

Boss likes 'er air.. full blast..

Originally Posted by LMP

Resistor not used with high speed. Check high speed relay and socket, a common problem specially with those using the high speed setting for long periods. On high, this is 25 amps pulled through wires and relay contacts...a little more than the design value of those components, it seems.
www.avigex.ca/xport/heaterrelay.jpg
www.avigex.ca/xport/hvac_diagram_front.jpg

Last qvestion.. Is the fan a press or bolt on to the blower motor? With a bolt on, they sell the blower motor seperate & cheaper, & you can use the old fan ..so i'm told. I'll have a look at the old one first..might be some evident reason for the chirping noise at the low speed setting in winter (leaves, debris, dirt etc..).

[LMP]

Originally Posted by 96tsport

Bingo! The #80 & 37 pins were visibly burnt ..Boss likes 'er air.. full blast...

..probably 30 and 87....great anyway if you fixed it....
both fans versions..that is bolt on and press on..were used and if you get a complete motor and fan unit from salvage, one or the other will be OK
however, beside the chirping noise, "full blast" for long periods is sufficient as the explanation for the situation you found.

[96tsport]

Originally Posted by LMP

..probably 30 and 87....

[96tsport]

Ok, got around to pulling the blower motor & didn't see a bolt on the fan so assumed mine is a press on; was dated 96 so assume original.

Had a ~ tuff time pulling it out, finally figured out 2 bolts for the coil pack then moving it aside & had to unclip & move aside a wire loom. Still didn't come out easy & ended up snagging & pulling hard to force it out. The plastic fan isn't very strong & is sharp enuff on the edge of the blades that it is easy to get small cuts on the fingers ..if not careful.

Decided to try & lube it to see if the chirping squeaking noise'd go away & reinstalled it. Seemed to help but then on high setting, turned into a loud vibrator that could be felt (big time) in the car & heard from a distance. Dunno what that was about but prob had to do with forcing the thing out & maybe damaging the fan though I couldn't see anything evident when I pulled it out again; lot easier this time. Was a bit worried that I may have bent up the mounting hole & would have that vibration noise/prob with the new unit

Anyway, ordered a new unit with a press on fan but it came with a bolt on setup;went in without a hitch ..& boss is happy ..likes 'er air cold & heat ..full hot..

[candleloria]

I have the same problem on 00 Gran Prix. No speed 5. My additional problem is speeds 1-4 appear to work but stopped blowing out any vents. This has happened twice when I traveled into a colder area. Is it possible there is a damper freezing shut that shuts off the air flow in addition to the problem of not having any high speed on the blower? We replaced the blower motor last year and then had a problem with air flow. Speed 5 never did work after the blower replacement.

[LMP]

If fan works on lower speeds, then the fan is OK also for high speed: fan has one winding only. High speed is controlled by a separate relay in former year models...but in 00, GP or TS(montana), the HS relay is imbedded with the resistor block.... check

[96tsport]

Looks like the high speed relay broke after ~ 4 mths. Pulled it off & pins looked normal compared to the original's that were burnt.

Thought the relay was only for high speed but after I pulled it, fan switch didn't work at all; prolly just get another one.

[96tsport]

Had a closer look at the ~ new relay in better light & there was definitely slight (brownish, burnt) overheating discoloring of the #30 pin that stood out from the rest, though the base wasn't melted & overall wasn't nearly as bad as the original that failed.

Folks replaced it under warranty & we figured the old fan blower motor (now replaced) may have caused the early failure of the first replacement relay.