Fan controls not working correctly

[opie521]

I'm trying to work out all the kinks in this '97 Bonneville I just bought a few weeks ago. This forum has been a great help, so here goes the next issue. The fan controls for the air and heat only work on the middle two settings. Low and hight give me nothing, but the two settings that do work give a low and a high fan speed. It works, so it's not that big of a problem, but if there is a simple way to fix it to get all 4 settings I'm all for it! It's just the normal air controls, no climate control or any of that jazz. Any Ideas?

[bill buttermore]

Don't know what year the electronic blower control module replaced the resistor pack, but that sounds like your problem. The BCM (or resistor pack) sits in the top of the heater duct on the firewall side of the engine under the relay center. It is held in place with one or two screws. The resistor pack is cheap; the BCM is expensive.

[imidazol97]

I'm trying to work out all the kinks in this '97 Bonneville I just bought a few weeks ago. This forum has been a great help, so here goes the next issue. The fan controls for the air and heat only work on the middle two settings. Low and hight give me nothing, but the two settings that do work give a low and a high fan speed. It works, so it's not that big of a problem, but if there is a simple way to fix it to get all 4 settings I'm all for it! It's just the normal air controls, no climate control or any of that jazz. Any Ideas?

If yours is the manual system, there is a resistor pack that controls the lower three fan speeds. That resistor unit is on top of the air plenum close to the blower motor. It is in the air stream for cooling.

The relay in the Relay Center is a two contact relay and switches from a wire for the 3 low speeds to a direct wire for the high speed.

If the middle resistor wire is broken in the resistor pack, you would have speed 3 and high speed which is direct, while low speed 1 and 2 would not work.

You need to raise the Relay Center to allow access to the resistor pack and inspect it for a broken wire. It is held by a couple of bolts and can be pushed up a couple inches after removing them.

Then you may have a problem with the high speed connection through the relay in the relay center. The high blower relay is the 4th from the passenger side.

[opie521]

Thanks for the tips. Can anyone send me a diagram? I've been stuck on this for almost a month and it's Hot here in Kansas!

Thanks!

[1oldman]

Hi, I would try to help, but all my books are only good to '95. If you are going to keep the car, i strongly suggest you invest in a set of Helms manuals printed for GM and a Chilton's. I paid $94 for my Helms set a number of years ago. I saw them recently go for $30.

[willwren]

http://www.pontiacbonnevilleclub.com/fo ... =45&t=2432

4th pic down shows the location, previous pics show how to get to it. Yours will look SLIGHTLY different. That article is about cleaning the core, so do that while you're in there, and you'll restore any flow caused by restrictions as well.

Pardon the dirty engine and car. Normally I can eat off it.