Question about 2005 GMC Sierra
Go to Autozone.com and sign up and register your truck for FREE. Then you can scroll down to the Diagrams section which also has Fusebox and Powerbox layouts.
The Relays are usually in the Powerboxes under the hood. Sometimes the horn relay is identical to other important relays like your cooling fan relay.
If the layout shows this is true and the part numbers on the case of the part matches, then you can switch the relays and see if the fan works or the horn works.
The diagrams are also for the chassis and will help you trace the wires by color and will indicate through the wiring pattern of whether the relay is in the Powerbox or next to the fan.
Posted on Feb 08, 2012
Relays are located left end of the instrument panel.look inside owners manual in glove compartment, it has all fuses and relays locations.
Posted on Feb 08, 2012
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this 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.
Here's a link to this great service
Posted on Jan 02, 2017
The switch or the wire harness at the blower motor has gone bad. The highest setting 5 has no resistor, so the blower runs on high but the high current flow ends up burning up the switch's contact on that setting or the resistor wire harness at the blower motor has gone bad. Common would be the switch it self, if the switch is good. Then it's going to be the wire leads at the speed resistor by the blower motor under the glove box by the passenger leg compartment. Keep me posted, be glad to help you get your Sierra running 100% again soon.
Posted on Jan 06, 2010
Check coolant level. Check for heat at the heater hose going from water pump to heater core at firewall. Check to see that cable is moving coolant control valve from the closed to open position. Low mileage so it shouldn't be plugged heater core.
Posted on Jan 07, 2010
Testimonial: "You were absolutely correct. Low coolant level. Put in some 50/50 and we're nice and toasty now, but need to find out why coolant was so low. Thanks."
check pins at the blower motor resistor
a- tan- med 1
b- yellow- low
c- pink - med 3
d- light blue- med 2
e- black- ground
f- orange- high
g- red- battery +
it could be the resistor
Posted on Mar 04, 2010
Tips for a great answer:
Jun 28, 2016 | 2010 GMC Sierra 1500
Dec 22, 2015 | 2005 GMC Yukon XL
Sep 13, 2015 | GMC Cars & Trucks
Jan 27, 2015 | 2005 GMC Sierra
Oct 28, 2017 | 2003 Ford Escape
Nov 01, 2010 | 2005 GMC Sierra
Mar 05, 2010 | 2005 GMC Sierra
May 09, 2009 | 1991 GMC Sierra
1,658 people viewed this question
Usually answered in minutes!