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Can I use a simple multimeter to check if power is getting to my blower motor? I have the motor out, have checked it and it is good. Now I want to test and see if power is coming thru the wires to the motor. Thanks. As you can tell, automobile electricity is not something I know enough about to diagnose.
I don’t see why you couldn’t use one and see what voltage each speed does.
were you having issues?
mine started to quit and worked fine outside the car but not installed.
of course triple check grounding.
my fan here for 79 https://www.corvetteforum.com/forums...d-working.html
I suggest a test light.
This will verify amps not just volts.
too many times I measured with dvm only to find no power/amps were there even though the meter said there were volts
I don’t see why you couldn’t use one and see what voltage each speed does.
were you having issues?
mine started to quit and worked fine outside the car but not installed.
of course triple check grounding.
my fan here for 79 https://www.corvetteforum.com/forums...d-working.html
Thanks. So, in the plug, stick the red in one side and the black in the other side? Then read the meter at each setting of the fan switch? That's how basic my instructions need to be LOL.
I will also see can I find my test light, used to have one, not sure I still do.
Yes, black to a known good ground like the engine. Red to the wire that went to the blower. Start with the fan switch on HIGH, it should show a full 12+ volts if the motor isn't running. Since the blower isn't connected you'll still get 12 volts or so on all the lower settings too. You need a load like the blower to really test the fan switch. Did you run a test 12V wire from the positive lead on the alternator to the blower to see if it would run? It it runs full speed then it's good.
If your blower is not working on the High setting the first place to look is the 30 Amp fuse at the driver side fender.
Circuit #40 ORN wire from inline 30amp fuse (driver side fender area) is the common side of the high speed relay.
1) Place blower switch to high, if you have 12V on DK BLU wire at blower relay than the switch is good.
2) With blower switch to high check for power at the blower relay ORN wire, if you have 12V the fuse is good.
3) With blower switch to high check for power at the blower relay PPL wire, if you have 12V the relay is good.
Outside of wire issues there are only 4 components in the HI Blower system. 1) Console switch, 2) 30A Fuse, 3) Blower Relay and 4) Blower Motor.
If the blower motor is working on lower settings the motor is good.
First, are we sure Kansas123 car is optioned with A/C?
"If" not, completely different circuit...
"If" not, there is no High Speed Fan Relay.
"If" not, is there a need for the 30amp fuse located around and below the master cylinder?
Location of resistor in a NON A/C car...
The plot thickens...
When the blower was out of my 69 factory ac i tested it with a battery charger.
With it laying on the ground hook ground to motor housing and red to power wire. Just touch it. That motor really spins!!!
i did this to confirm it worked. Just had a bad ground.
VS
Yes, black to a known good ground like the engine. Red to the wire that went to the blower. Start with the fan switch on HIGH, it should show a full 12+ volts if the motor isn't running. Since the blower isn't connected you'll still get 12 volts or so on all the lower settings too. You need a load like the blower to really test the fan switch. Did you run a test 12V wire from the positive lead on the alternator to the blower to see if it would run? It it runs full speed then it's good.
Exactly what I was looking for. And I do have a/c. I'll do some testing as suggested. Then see how it does using the controller switch.
A Power Probe is an awesome tool for problems like this. On the 1968 it takes minutes to connect the Power Probe and apply 12 volts to the red wire feeding the blower motor. The Power Probe is a very valuable tool when working on Corvettes as once it is connected to the battery the tool has both (+) and (-) available at the tip based on the position your finger is on the rocker switch. It has a built in circuit breaker to protect the wiring system. I bought one and starting finding uses for it everywhere.
Yes, black to a known good ground like the engine. Red to the wire that went to the blower. Start with the fan switch on HIGH, it should show a full 12+ volts if the motor isn't running. Since the blower isn't connected you'll still get 12 volts or so on all the lower settings too. You need a load like the blower to really test the fan switch. Did you run a test 12V wire from the positive lead on the alternator to the blower to see if it would run? It it runs full speed then it's good.
Well I finally got around to testing the wires to the fan. The voltage is measuring about 11, I figure it's a bit low cause I have been using energy and haven't been driving it so the battery is down. The culprit turns out to be a stray wire unaccounted for, which turns out to be the ground. Last summer when I was messing with the a/c I removed this wire (was grounded on an a/c mounting bolt) and I had put a piece of tape on it to protect it from touching anything. Turns out, I never hooked it back up. Nice fat wire for better ground. I think I am good to go, now I have to put the console back together ugh... I had removed the fan speed switch to test and clean it, that is one )**^%(#%@$& OB to remove and replace. Took me 2 hours. I hate the console, the dash, the .... Thanks for the information.
@kansas123 just went through troubleshooting my 68 fan and found the previous owner had cut the two ground wires (there were two black wires) that were to go to a space attached to fan house in engine compartment. Reconnecting that ground was the fix. Not sure why the spade was removed on mine.
04-05-2023, 07:57 PM
How to test power going to blower motor
