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Assistance/ Blower Motor only Works in Lower Speeds
Seeking some assistance for a 1986 Cutlass Supreme Brougham, namely the blower motor components. The blower motor was/is only working on the lower three or four speeds, 'not high'. It just cut out without any notice. I replaced the resistor, then found out the resistor controls the lower speeds, as the high speed is bypassed. Then I replaced the high speed relay, then found out that the high speed relay was only suspect if the motor was not working. I replaced the old resistor and relay. Now, the high speed works. I am at a loss to explain this problem. Can any provide any input or assistance here.
* There is no fuse inline, rather only at the fuse block. The only other items connected inline are the switch and the blower motor itself. It cannot be the switch, for the system is now working on high. All replies are welcome.
Last edited by synoptic12; October 20th, 2019 at 05:56 PM.
I'm sure it was the relay, or the switching wire to the relay from the speed switch. Once common problem. Relay wasn't really spec'd to handle the current and inrush current on blower spool up. Glad you got it fixed, no high speed blower in the winter is a drag, how well I know.
I'm sure it was the relay, or the switching wire to the relay from the speed switch. Once common problem. Relay wasn't really spec'd to handle the current and inrush current on blower spool up. Glad you got it fixed, no high speed blower in the winter is a drag, how well I know.
* How could it be the high speed relay when I placed a new relay in and it did not work? After replacing the "old" relay, the high speed functioned once again. In reality, three or four speeds do work well. It may take a minute or so more to heat, but works.
Have you used a VOM or test light to check if there is power coming into the high speed relay? That might be a good place to start before randomly replacing parts.
Have you used a VOM or test light to check if there is power coming into the high speed relay? That might be a good place to start before randomly replacing parts.
* No did not test. Process of elimination I prefer. If there were no voltage coming in, the blower would not work. I replaced all the components but the switch and blower motor. I stopped at that point after installing the old parts once again, 'after removing the 'new' parts. I'll check the switch when I get a chance. The parts are cheap enough. Thanks.
* No did not test. Process of elimination I prefer. If there were no voltage coming in, the blower would not work. I replaced all the components but the switch and blower motor. I stopped at that point after installing the old parts once again, 'after removing the 'new' parts. I'll check the switch when I get a chance. The parts are cheap enough. Thanks.
Well, that's your first mistake. Try looking at the wiring diagram in the chassis service manual FIRST. There are two separate power sources for the blower motor, one for low speeds and one for high speed only. Two separate wires, two separate fuses. Or, feel free to just throw money at the car by replacing parts that aren't bad. Your call.
Well, that's your first mistake. Try looking at the wiring diagram in the chassis service manual FIRST. There are two separate power sources for the blower motor, one for low speeds and one for high speed only. Two separate wires, two separate fuses. Or, feel free to just throw money at the car by replacing parts that aren't bad. Your call.
* I'm well aware of the wiring schematic in the Oldsmobile Chassis Service Manual (1986). I know that the red is hot and proceeds directly to the battery in bypassing the resistor, that only controls the lower speeds. The Purple wire is working fine which is adjoined to the resistor, and the ground (Black) is fine. My question was: How in the world is the blower motor working on "all speeds" including 'high' after reinstalling the original 'resistor' and 'high speed relay' after trying a new resistor and relay * *Note: The new relay I purchased stated “Standard Relay” whereby the Olds’ Chassis Manual refers to the relay as ‘high speed’. * There is only one fuse located in the fuse box, not two. You may be referring to an older Olds.
* There is only one fuse located in the fuse box, not two. You may be referring to an older Olds.
You MIGHT want to look at the wiring diagram again...
I never said there were two fuses. I said there were two power sources. The low speeds are fed by the A/C fuse in the fuse box. The power to the high speed relay comes via the red wire that is connected directly to the battery terminal on the starter solenoid via a fusible link.
* CIRCUIT OPERATION
The only area left is the switch which may be faulty. * The blower motor speed is controlled by the ‘Blower Switch’ in the A/C Control Assembly. In the OFF position, no voltage is applied to the Blower switch and motor. In the LO Blower Switch position, all of the Blower Resistors are in the circuit with the motor so that it runs slowly.
In the M1 and M2 positions, the Blower Switch by-passes some of the resistors, increasing the motor speed. For the above reason is why I changed out the resistor for it states, “some of the resistors” therefore meaning ‘not all’. At least, that is what I interpreted. For HI speed operation, Battery voltage is supplied through the ORN (Orange) wire to the coil of the A/C Blower Relay. The relay is energized and its contacts supply battery voltage directly to the Blower Motor from a fusible link. (Apparently for V6 Vin A only). With no resistors in the circuit, the Blower Motor runs at high speed. That last statement is somewhat convoluted as the above clearly states “some of the resistors”. This can only be construed as an interruptive error. Your opinion is more than welcome here.
1986 Olds Cutlass Blower Switch Not Working on 'HIGH'?
May have posted prior. Seeking assistance in determining the cause of my blower not working on "High" Speed. I replaced the resistor, relay and blower control switch. There is nothing left but the blower motor and the HVAC Blower Control Switch ACDelco GM Original Equipment 15-7004.
Does the HVAC Blower Control Switch ( 15-7004) control the speed? All assistance is appreciated. HVAC Blower Control Switch ( 15-7004) ACDelco 15-71352 GM Original Equipment Heating and Air Conditioning Blower Control Switch
On Chevrolet's of that vintage there was a square black connector in the harness on the right valve cover that frequently would have burned connections, look there. Is there voltage to the relay? Full battery voltage to the relay goes out of the relay to the blower motor when the relay gets voltage to close sent from the blower switch in Hi position.
Slower speeds other than Hi send power through the blower resistor to reduce voltage/speed.
Last edited by Sugar Bear; February 9th, 2020 at 10:35 AM.
On Chevrolet's of that vintage there was a square black connector in the harness on the right valve cover that frequently would have burned connections, look there. With the key on does the purple wire to the relay have voltage?
Good luck!!!
I've already performed those tasks. No burned connections and the purple wire is fine.
*Does the HVAC Blower Control Switch ( 15-7004) control the speed? "Top Picture"
Yes the blower switch controls the speeds. The lower speeds by sending it through the the blower resistors and the high speed by sending a signal to the relay to close and send full battery voltage to the blower. IIRC there is a brown light gauge wire at the relay. If it gets voltage with the switch in Hi the blower switch is working.
I've re-read your post and my comments apply to the black switch on the bottom right. I don't think the top pictured switch controls the speed but am waiting for someone else to chime in as I don't want to send you down the wrong .path
Good luck!!!
I've re-read your post and my comments apply to the black switch on the bottom right. I don't think the top pictured switch controls the speed but am waiting for someone else to chime in as I don't want to send you down the wrong .path
Good luck!!!
Thanks much. The top part is referred to as a blower switch that I just ordered. There is nothing left but the motor. You could be correct but I cannot acquire a positive answer, even from the auto parts stores.
Link: https://www.autozone.com/cooling-hea...=&model=&year=
I just spoke with Mike at Jegs and he said he was uncertain of the function of the 15-7004. However, Mike said the 15-71352 should have taken care of the problem. Mike also said that the 15-71352 could be connected (adjoined) to 15-7004. In so that one part may not work without the other, if that makes sense. Mike assured me almost that the 15-7004 should solve the problem. I hate to believe its the blower, especially if it's operating on all three speeds with the exception of 'High'.
A.) Replaced the relay
B.) Replaced the resistor even though it does not control 'high' speed, only the lower three speeds; in bypassing the high speed which runs directly to the motor.
C.) Replaced 15-71352 Blower Control Switch.
Any input here is appreciated.
You may have a new, defective relay. I had an 86 Monte Carlo that used to have that problem, and replacing the relay cured it for a time. Why they didn't last as long as the original, I don't know, unless there was another problem, or the relays I was buying were poor quality. Eventually I ran my own feed to the blower with a toggle switch, and when I wanted the high speed, I just put that switch on. Not very pretty, but it worked.
You may have a new, defective relay. I had an 86 Monte Carlo that used to have that problem, and replacing the relay cured it for a time. Why they didn't last as long as the original, I don't know, unless there was another problem, or the relays I was buying were poor quality. Eventually I ran my own feed to the blower with a toggle switch, and when I wanted the high speed, I just put that switch on. Not very pretty, but it worked.
Thanks much. I'll give it another try with a different relay after I install the 15-7004. This is a real pain.
The HI speed blower is powered by the red (always hot) wire through the relay which does have a fusible link. The relay has 3 inputs, the orange wire, red wire, and dark blue wire. And two "outputs"- the purple wire to the fan motor, and the black ground wire. If the relay is bad, you can, and then jumper the purple and red wire and the fan should run. At least check for voltage at the red wire. It may be the relay as mentioned.
The fan blower speeds are generally controlled by the black switch, GM p/n 16032480. The orange wire comes from the black fan speed switch for high position. The orange wire energizes the solenoid in the blower relay when the switch is set to HI to swap the power supply from the resistors (Dark blue wire to the relay) to allow full power from the red wire to power the fan motor in high speed. I'm not aware of any fuse for the high speed fan on a G-body. Not saying there isn't one, I've just never seen one.
That orange gizmo is the mode selector switch, GM p/n 16001570. It is controlled by the top lever control on the HVAC unit face. When you select "Defrost" or "A/C" or "Vent" modes, it switches things like the A/C compressor on or off as needed, junk like that. As for power supply, It sends power to the fan switch in any position except OFF, obviously. It also sends power to the relay through the blower resistor BROWN wire for fan LOW speed (full on resistor). The power to the relay for the lower speeds from the resistors is the dark blue wire. The tan and medium blue wires on the resistor are the medium low and medium high position inputs of the fan switch.
If that made sense, great. But I would check for voltage at the red wire. If you have voltage there and have the rest of the fan speeds, my bet is on the relay.
It cannot hurt to change out the mode switch or the fan switch if you have any doubts, and especially if you have them out already. They're probably 34 years old...
The HI speed blower is powered by the red (always hot) wire through the relay which does have a fusible link. The relay has 3 inputs, the orange wire, red wire, and dark blue wire. And two "outputs"- the purple wire to the fan motor, and the black ground wire. If the relay is bad, you can, and then jumper the purple and red wire and the fan should run. At least check for voltage at the red wire. It may be the relay as mentioned.
The fan blower speeds are generally controlled by the black switch, GM p/n 16032480. The orange wire comes from the black fan speed switch for high position. The orange wire energizes the solenoid in the blower relay when the switch is set to HI to swap the power supply from the resistors (Dark blue wire to the relay) to allow full power from the red wire to power the fan motor in high speed. I'm not aware of any fuse for the high speed fan on a G-body. Not saying there isn't one, I've just never seen one.
That orange gizmo is the mode selector switch, GM p/n 16001570. It is controlled by the top lever control on the HVAC unit face. When you select "Defrost" or "A/C" or "Vent" modes, it switches things like the A/C compressor on or off as needed, junk like that. As for power supply, It sends power to the fan switch in any position except OFF, obviously. It also sends power to the relay through the blower resistor BROWN wire for fan LOW speed (full on resistor). The power to the relay for the lower speeds from the resistors is the dark blue wire. The tan and medium blue wires on the resistor are the medium low and medium high position inputs of the fan switch.
If that made sense, great. But I would check for voltage at the red wire. If you have voltage there and have the rest of the fan speeds, my bet is on the relay.
*You said GM p/n 16001570 sends power to the relay through the blower resistor. So, if GM p/n 16001570.is faulty, no power would be sent to the relay through the resistor. Is that part number ACDELCO 15-7004?
Some quick pics. RELAY
I'm having an issue uploading some images: Stopping at 90 %.
It cannot hurt to change out the mode switch or the fan switch if you have any doubts, and especially if you have them out already. They're probably 34 years old...
Thank you truly. Yes, it makes perfect sense.
Last edited by synoptic12; February 9th, 2020 at 05:51 PM.
I changed out the fan switch. Purchased the mode switch and will install that soon. Is ACDELCO 15-7004 the mode switch you are referring to? There's nothing left but the motor and it could not possibly be the motor.
Those are my pictures you uploaded.
Last edited by synoptic12; February 9th, 2020 at 05:48 PM.
I changed out the fan switch. Purchased the mode switch and will install that soon. Is ACDELCO 15-7004 the mode switch you are referring to? There's nothing left but the motor and it could not possibly be the motor.
Those are my pictures you uploaded.
Yes. 15-7004 is the mode switch.
I didn't upload your pictures. Unless something got slammed in the forum software and merged something. I sure as heck didn't do it.
The M1 and M2 speeds are controlled by the resistor only as the high speed relay is bypassed. MI and M2 speeds are functioning properly, except 'high' speed. Exactly where is the second or (inline fuse) located? You state on the starter solenoid, which I cannot locate. Still working on the problem. Backprobed the resistor and the ohms specs are correct. I ordered a new relay which controls the function of high speed. Maybe, the first was defective (Four Seasons). I'm receiving and ACDelco relay. Having a difficult time finding parts or legitimate parts as O.E.M. It's not the motor for I've changed that out, along with the resistor, relay, rotary or (selector switch) and high speed switch. Again, where is the inline fuse that I cannot locate, supposedly on the solenoid?
May have located the fusible link which may be the cause. Is there actually a fuse inline? I'll have to place the car on a lift. Someone I knew installed a starter for me, maybe incorrectly. Diagram below.
To be more specific, I just performed Test D in backprobing the circuitry. RESISTANCE
A.) BRN and TAN ----------- 1.5 ± 1 ohm > My Reading 3.8
B.) TAN and LT BLU ------- .7 ± .5 ohm > My Reading 1.9
C.) LT BLUE and DK BLU------- .2 ± .1 OHM > My Reading 1.6
* Can any determine if the resistance on the resistor terminal is correct? The values do not seem to correlate with the set resistance.
Last edited by synoptic12; February 16th, 2020 at 02:55 AM.
Performed Test E for Voltage Test:
1.) ORN Wire ---- 11.9 v > Battery
2.) DK BLU ----- 11.9 v > Battery
3.) RED ------------- 9.5 v > Battery
The red wire leads to the fusible link on the solenoid on the starter. Could this be the problem with blower fan not working on 'high'. The 9.5 v on the red wire is not the same value as on the ORN & BLU wires. Can any provide any assistance here?
So basically what I told you back in Oct in post #6. Now figure out why there's a voltage drop on that wire. Could be a bad fusible link. Could be a loose crimp connection where the fuse link wire splices to the regular wire. Could be a dirty connection to the starter post. The easy thing to try is to bypass that wire completely and temporarily connect a wire directly from terminal "B" on the relay to the + terminal on the battery. If the fan works in high speed with that bypass wire in place, you've found your problem.
October 19th, 2019 | 04:25 PM
Assistance/ Blower Motor only Works in Lower Speeds
of that vintage there was a square black connector in the harness on the right valve cover that frequently would have burned connections, look there. Is there voltage to the relay? Full battery voltage to the relay goes out of the relay to the blower motor when the relay gets voltage to close sent from the blower switch in Hi position.
