IMO, Cheap preventive maint so might as well replace them both. Oh yea, How much are they?
Thanks for the response, John. That's what I was thinking. I have three relays: 1) fan speed high, 2) fan speed low, and 3) fan control. I tried getting relays from O'Reilly, but they gave me a smaller, rectangular one for one of the slots, whereas mine are all square. All of mine are Delphi. Two are marked 8864, and one is marked 8865. I returned what I bought so I could find out what the current part numbers are, and get the correct units.
As far as the cost of the fans, I bought them from Amazon for $163; $176 after CA added its bloodletting. I checked with RockAuto, but they were still a few dollars more. I see today that the fans went up $20 since I bought mine. I replaced mine because the motor on the right was hanging up and not turning on unless I tapped it. Both of the motors seemed fairly sluggish, also. Sure enough, after installing the new fans, the difference in the amount of air moved is very significant. I know there's some difference between the fan blades and the higher wattage motors, but this was huge.
As far as the relays, are they all the same between the 5/7 blade units and the 7/9 blade units? The OEM part numbers listed on the TYC label correspond to the heavy duty cooling parts I've looked at on gmpartsdirect.com. I just want to make sure I get the correct relays so I don't damage the new fans. Thanks.