Question about 2004 Chevrolet Silverado 1500 Crew Cab
Thanks for your help. I'm not too experience with electronics. I don't understand how 12 volts can continue to power blower with fuse out. How is power not disconnected. If there continues to be power circulating, why does it not stay on with engine off as it does with fuse in? It's like it's working backwards. Is it a hazard to run without fuse?
There are two fuses for the fan. One is probably a 20 Amp in the fuse panel in the cab and marked "Heater". or "Heater/AC" The second is under the hood may be marked Heater, Blower, or Fan and should be 30 Amp. The one in the cab supplies switched 12 volts to the fan speed switch. The one under the hood supplies the 12 volts to the relay. The relay is normally energized by the 12 volts through the 20 Amp fuse in the cab and through the switch. I think you find that the fan has the normal speeds except for missing HI with the underhood fuse removed, and will turn off with the ignition that way. There is no hazard in operating it that way but you may want to replace the resistor/relay assembly before it gets too cold. The relay is a pretty trouble free device in most cases, maybe you can find a deal on a good one at a junkyard.
The whole idea with the relay under the hood started back in the Sixties believe it or not. There is considerable voltage drop in the wiring between the fan switch and the blower fan motor. By adding the relay under the hood right next to the motor, the voltage drop was reduced, both by the shorter wire, and by using heavier wire to boot. The motor gets really close to the full system voltage when the relay is closed. In your case where the relay keeps the fan running, it can drain a battery rather quickly too!
Posted on Dec 18, 2008
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Dec 16, 2014 | Cars & Trucks
Jan 04, 2014 | Cars & Trucks
Dec 26, 2013 | 1996 Plymouth Voyager
Dec 04, 2011 | Cars & Trucks
Nov 05, 2011 | 2000 Ford Focus
Dec 17, 2010 | 1998 Honda Passport
Oct 24, 2010 | 1995 Honda Civic
Aug 09, 2009 | 1997 Honda Civic
Jul 24, 2009 | 1997 Lexus LS 400
Jul 09, 2014 | 2004 Chevrolet Silverado 1500 Crew Cab
538 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: