'97 Olds 88 LS Air and blower problem/fixes

I am writing this in the hopes that it will help someone else out. This is a long post, so I apologize in advance to the moderators. If it needs editing, please let me know or feel free to do it yourself to make it work.
I had a two-fold problem with my 97 Olds 88 LS air conditioning system. It is the manual system, not the automatic system. My problems were:
1) The air conditioning would not always blow cold, sometimes it was cold, sometimes warm air would come out of the vents. Never made any real correlation to when it would happen, or under what conditions, just that sometimes it worked, sometimes it didn’t.
2) The blower fan stopped working on high a long time ago, and I just lived with it. Sometimes it would come on if I cycled the switch a few times or hit a bump or whatever, but never with any consistency. It came on one time when I hit the dash, but in the end all this did was confuse me with regards to what the real problem was. Then it started failing on the lower speeds and I had no air movement at all unless I rolled the windows down. Less than ideal in Dallas in August.
Here’s a description of the problems and fixes.
1)The air conditioner blowing warm air problem was due to a faulty Heater Blend Door Actuator. It would get hung up partially open and blow warm air into the cabin mixed with the cold air. Did A search for this on RockAuto.com, and came up with this for $46:
ACDELCO Part # 1571835 {#16124942}
ACTUATOR,TEMP VLV w/A/C AUTO CONTROL(C61)

From AutoZone, $99.99, quite a bit more expensive.
Dorman/A/C Heater Blend Door Actuator, Part number 604-123

To be perfectly honest, I did not order the part. After researching this forum, I found out that the actuator is easily accessed by dropping down the glove box with two rubber tabs in the back of the glove box that can be pulled toward the center and the glove box will drop down easily. If the problem happens anymore, I will just pull over, drop the glove box, and slide that arm over to get the cold air flowing. A nuisance, but the car is old, the part is $46 plus shipping, and it looks to be a little bit of a pain to get at the fasteners holding it in place.
2) The fan problem was the high speed fan blower relay. Again, through research on this forum, I found out that the high speed fan has its’ own separate relay. But which one, and where it was located was a super long process and I never could find the definitive answer. Is it on the driver’s side fuse panel, the passenger side fuse panel, under the hood, and if it is there, how the heck do I know which one since none of them have a handy description anymore of what relay is for what system? They probably did at one time, but the car is old, it’s been worked on a lot over the years and none of the markings are there or in the owner’s manual, and the Haynes manual is so generic that it is downright confusing at times.
Well, it’s located under the hood up high on the firewall, in the right side Maxifuse/ Relay Center. It is the black colored one (the others were gray), the third one in from the passenger side fender. Starting from the passenger side fender, there were two gray ones, a black one (the culprit), three blank spots, then two more gray ones. Please don’t ask what the others are for, I have no idea, but I do know they are all good, cuz I tested them, which I will go into in a little bit. They are removed putting a thin flat tip screwdriver underneath on the metal mounting slots, push down in the center and pull them out. They will have to be worked back and forth quite a bit since they have been there for a long time. Then you remove the green locking tab, push down the little plastic retainer and work the relay off of the electrical wiring. This will have to be worked back and forth quite a bit as well.
Here’s a description from AutoZone, it cost $17.99 (around $10 at RockAuto.com, but AutoZone is 5 minutes away):

Duralast/Relay - Blower Motor
Part Number: 19265
Alternate Part Number: 41-5134

Time for some added information that my research turned up, a lot on this forum and other places for the problem, the fix, the location of the parts on the car, etc. I actually learned a lot doing the research that will help me in the future. There are wonderful videos on YouTube of how to test a relay, but they didn’t cover the 5 pin relay that the high speed fan has. So more research was in order. Through some more research, learned how a relay works, and what the pins actually go to or come from. Learned how to use a multimeter to test for continuity (so simple).
I suspected that the problem with the fan was electrical, but didn’t know what it was. Thought it was the switch on the panel, but didn’t want to pay almost $500 to find out, so I put this off for a long time, until the lower fan speeds quit working. I was at a junk yard getting a fender to replace the one that my son dented by running into a shopping cart (but that is another story), and figured what the heck, let’s get the HVAC Controller for $35 and see if it fixes it. I was truly thinking this was the problem. Well, I put it in and I had the exact same problem, so that eliminated the switch as the culprit for both my issues.
I figured out that the heat blowing while the AC was on was probably the Heater Blend Door Actuator, which it was. I found out it was behind the glove box on top of the ducting, in plain sight. I just started the car and operated the controls a few times, and sure enough, it was sticking, allowing hot air to be mixed with the cold air. Problem found, solution was now known, but as I said, I did not buy the part to fix it.
So then I figured out that the high speed fan relay was probably the problem for the lack of a high speed on my blower fan, which it was. I still didn’t know where it was located or how to tell it was bad. Found out that it was probably on the firewall under the hood, so I just started pulling the relays one at a time and testing them, with my new knowledge from a YouTube video.
You can use a 9 volt battery or your car battery for power. Run some test leads or wires from the battery and touch pins 85 and 86, doesn’t matter where positive or negative are touching. You should hear a clicking noise that lets you know it is working. That click is an internal magnetic field being activated, which then moves an internal switch allowing electrical contact to be made inside the relay and power to flow through the relay to the blower motor or whatever else the relay is used for. There are relays for a lot of thing on the car such as air conditioning, cooling fans, etc, and a lot of them are the exact same relay, further adding to the confusion, at least for me. But the relay could still be working intermittently (remember how banging on stuff sometimes makes it work and how sometimes the high speed would come on when driving over a bump?), so the click doesn’t tell the whole story. You set your multimeter to test for continuity and put the leads on pins 30 and 87. If the relay clicks and then you get continuity (indicated by the multimeter showing something other than the number 1, and an audible tone on some multimeters) between 30 and 87 that remains on and isn’t a quick continuity that then goes off (indicating intermittent operation), you know it is working properly.
But what about testing the 5 pin relay, like the high speed blower relay? It has a pin 87A, which is where the low speed relay voltage normally flows through. It is normally closed allowing voltage to flow through, so there should be continuity between pin 30 and 87A until power from your test battery is applied to pins 85 and 86, then there should be continuity between pins 30 and 87. Please note, the audible click on my newly purchased relay was MUCH quieter than the old one, so pay attention.
I found out that the random third relay I pulled was not working properly by using this test method. So from that, I deduced that “Hey, this is probably my high speed fan relay!” bought a new one at AutoZone, put it in, and everything is working properly. YEAH!!!
But why did the high speed fan relay have any effect on the lower speeds? Figured out that the lower speed signal (voltage) is routed through the high speed fan relay before going to the blower motor, and that is what the 5th pin is for on the high speed fan relay. It is in a normally closed position, allowing the low speed fan voltage to flow through the high speed fan relay without being influenced by the high speed fan relay. I figured this out by looking at wiring diagrams (which I am not in the least good at deciphering, but I can follow a line from the low speed relay through the high speed relay to the blower motor).
I know I could have pulled relays and swapped them around, but there were none exactly like that in this location and I had read several times that not all relays are the same, and switching them could cause damage, blah, blah, blah. So, not knowing too much about electrical stuff and wanting to learn anyway, I did it this way.
Sorry for the length, but thought this whole story and thought process might help someone. I appreciate all the information others have shared on this forum, it has helped me out with other things, and I wanted to contribute if possible. I don’t often check here, unless I am having problems, but feel free to send any questions through me email address, [email protected]

Your post was very informative. However, I have not been able to find the relay for the blower motor. It is not in the location where yours was. Just wondering if anyone has any idea where else to look? I am troubleshooting a similiar problem.

If you have the auto HVAC then you have a power module.

Yeah, that's the only thing I can think of is that you may have the auto HVAC like maxwedge says. And from reading on here, he knows about 1000X more than I do. I know just enough to be dangerous. :lol:

Where would I find the power module and is there a way to check to see if it is operating correctly? I have no blower at all, was working fine then nothing. Had the garage check it out and they thought the control panel on the dash was bad because it has a small burnt circle on the lower right hand corner of the glass. I have another panel that is supposed to be good which did not correct the problem. It too has the small burnt looking circle in the lower right hand corner of the glass. Any suggestions?

Not positive avbout the location on this car but there are usually on top of the evap case under the hood, r/s against the fire wall, go to Rockauto.com and they should have a picture, I checked it is listed under blower control/module. Good pics.

I went to rockauto.com but they show a blower motor relay for my 1997 Olds Regency as opposed to a power module. That is what I cannot find. If I turn the blower switch on an off I do hear clicking which is very faint under the hood but louder coming from beneath the passenger side dash. I have looked there and still cannot find a relay. Any other suggestions?

Do you have the automatic climate control?

I believe I do. If you set a temp it will maintain that temp.

With autotemp, you have a blower control module.....it is located in the same place the resistor block would be.....it is under the fuse relay center in the engine compartment on the firewall, more towards the passenger side....just follow the blower motor wires back to it...

Actually this car must be unique. The wire from the blower goes back through the firewall. I also cannot find anywhere that says there should be a module. There are several modules under the passenger side dash but I have not been able to determine which is clicking when the blower is turned off an on. Does anyone have any idea what a part number might be for such a module? Or where I might go to find such a part number? Everything I see calls for a relay not a module.

Ha, ha...it does not go through the firewall......it goes to a connection......what the harness is connected to, is the module.....I think there are 3-7mm screws....remove them and the module comes out vertically.....to do this, you have to remove the relay bracket above it(2-10mm nuts)....

If you hear clicking in the passenger compartment, under the dash on the passenger side, there is a relay center there....just look at the far right side and upward(have to remove the hush panel).....

I am back at it after a few days of being sick. I found the power module. Not sure what it does though. It looks like it only has a transistor in there with a pretty large heat sink. Is there some way to test it to see if it is good?

You could check for continuity across some terminals but I do not know what the test procedure is, but smell if it seems burnt most likely it is bad.

There usually is a 4 wire harness to the module.......two of the wires are power(usually red) and ground(black)....so attaching a test light to these two leads should light up.....if it doesn't, check each leg......third wire should be purple...this is the output to the blower and provides power to the blower....

I assume that you have manually varied the blower speeds, and checked for power at the purple wire to the blower motor and a good ground on the black wire......just have to disconnect harness to blower motor and attach test light to the two leads....if it does light, bad blower motor.....if it doesn't, once again check each leg individually.....one for power and one for a good ground.....if ground is good and there is no power on the purple wire, then we go to that fourth wire, which is usually grey with a black stripe....this wire is the blower speed control input.....this comes from the HVAC programmer.....I'm not sure what the voltage should be, but it should vary as you manually change the blower speed on the head.......if it does, then you need a module....if it doesn't, then the programmer has to be checked out....

The parts list on this system is control head, solenoid switch assembly, programmer, vacuum actuators, temp & solar sensors, electrical temp valve actuator, blower control module and blower motor....if dual system, extra temp valve and passenger control.....

Thanks for all the help. It looks like the power module under the fuse box on the firewall is the problem. Got to get a part and then will know for sure.