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  1. #11


    Quote Originally Posted by robs1992chevywt View Post
    does what work....i have voltage but it doesnt vary thats why im assuming the blower relay is bad i just cannot locate it
    there is no relay for speeds, the switch changes where the power goes through that resister pack in the top of the heater box, that it what controls speed, usually the slower speeds fail and high only works as its full 12v
    my 88 sas "mudwasp"
    88 chevy k2500, started as reg cab lb, now reg cab shortbox, sas 17'' of lift, 52'' front springs f.i. bbc , 79 dana hp 60 chevy outers, 14bolt ff spooled divorced 205 and cut 40'' gumbos
    1998 k3500 gmc crew cab dually L65 6.5TD 4l80e with a couple of mods

    bouncing truck avatar creator

  2. #12


    I think you will probably have to trace it the old fasioned way.
    Take that wire bundle that plugs onto the resistor pac(on the top of the duct in your pic) and follow it to the relay.
    I found a general gm circuit schematic of how the blower circuit works, but not specific to your exact vehicle.
    Here's the link:
    What u will be looking for is on pages 72-75. It's basically the same page repeated 4 times. select the page and rt click and select rotate clockwise so you can read it easier.

    For the low speeds the current goes thru the resistor pac, then thru the normally closed contact of the blower relay when the relay is DE-energised.
    When you turn on the high speed the relay is then Energised and sends direct 12V from a different fused circuit to the blower.
    You will have 2 different fuses that control power for the blower motor. 1 that is only energised when ign is on(for low speeds, and to turn on the relay), and one that is on all the time(only switched by the relay for blower high speed).

    Another option to try and find the relay, be very quiet, and listen for the relay clicking when you turn the high fan on/off.

  3. #13
    Sr. Apprentice DanPruski's Avatar
    Join Date
    Jan 2012
    Wasilla, Alaska


    okay, just looked it up, look under the hood, passenger side of the firewall, theres a black plastic cover (Power Distribution Center) its labeled on the cover as BLOWER, check that, it may be a fuse, relay, or fusable link. thats where i found online to check atleast.

    05 Silverado 1500 LS 5.3L.
    6" fabtech lift, 35x12.5 Nitto Mud Grapplers, 20x10 XD Monster wheels. MagnaFlow dual exhaust, AEM cold air intake, custom tune.
    35W 5K HID low,fog, 55W highs, Hi-6 Mod, black tail lights.
    Color matched front and rear bumper caps, fully debadged.
    5% tint all around, 35% full windshield with 10" 5% brow.
    7" pioneer touchscreen Double Din, 2 Rockford R1-12's under the seat with Rockford P300-1amp, Rockford prime speakers all around, LED interior Lights.

  4. #14


    Dan, i checked the cover and the only things labeled are. ground Fuel pump relay fuse junction block fuel pump relay optional relay ground
    there is no "Blower" on my truck is a pita

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