I have spent that last two days researching this subject online and at the library. This information is not in the Chilton's General Motors "Full-Size Vans" manual 28642 that I bought for this problem and others. The blower motor works intermittently and not in all positions of the fan speed switch. I would like to replace the blower motor resister but I can't find it. On trucks it is behind the glove box. The Van doesn't have one. Anyone know where it is located??
The book you mention is published by Haynes.
The blower motor is on the blower case.