Thermo Switch for elec fans - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jesse 67 c-10 · 06-10-2002, 12:41 PM

Been working on my truck some in the last while, a few problems I'm trying to figure out. I just got my electric fans hooked up, they work great turned on they drop the temp 20 degrees in about a min. at idle. The manual switch I put in works fine but the thermo switch doesn't turn on at all. There's power going to it and it's put in the rad 3" under the uper rad hose but I let the temp get to about 210 and it's sposed to turn on at 180, any tips?
Thanks
Jesse

383 Stroker · 06-10-2002, 01:01 PM

The thermo switch grounds the relay to activate the electric fans. This is the way you have it hook up right?

tom hand · 06-10-2002, 01:06 PM

The first thing I would do is test the switch. Take it in the kitchen and boil some water on the stove. Put the switch in some warm water. Now you need a VOM set on continuity and a cooking thermometer. Now add hotter water and use the VOM and thermometer to deside what tempature actually makes the switch operate.

Jesse 67 c-10 · 06-11-2002, 02:14 AM

The switch allows current through to turn on the relay, I'll try that with the boiling water, if it doesn't work I'll send it back, but maybe it will work after it clicks once in real hot water, I just don't want to get my engine that hot to see if it does!
Thanks
Jesse

06-10-2002, 12:41 PM	#1
Jesse 67 c-10 Registered User Join Date: Feb 2000 Location: Edmonton, Alberta, Canada Posts: 599	Thermo Switch for elec fans Been working on my truck some in the last while, a few problems I'm trying to figure out. I just got my electric fans hooked up, they work great turned on they drop the temp 20 degrees in about a min. at idle. The manual switch I put in works fine but the thermo switch doesn't turn on at all. There's power going to it and it's put in the rad 3" under the uper rad hose but I let the temp get to about 210 and it's sposed to turn on at 180, any tips? Thanks Jesse __________________ Edmonton, Alberta, 67 c-10, Long fleet, front disks, 5 lug rear end, 327 with Vortechs, edlbrock manifold, comp cams XE 256, 600cfm carb. Backed by a getrag 5 speed and 1 piece driveshaft. 1993 Dihatsu Hijet Jumbo cab 4x4, currently converting to battery electric power.

06-10-2002, 01:01 PM	#2
383 Stroker Registered User Join Date: Aug 2001 Location: Jesup, GA Posts: 571	The thermo switch grounds the relay to activate the electric fans. This is the way you have it hook up right? __________________ Video's of my Truck Racing 1967 C-10, 383ci Sbc, TH350, 3200 stall, 3.73 gear

06-10-2002, 01:06 PM	#3
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	The first thing I would do is test the switch. Take it in the kitchen and boil some water on the stove. Put the switch in some warm water. Now you need a VOM set on continuity and a cooking thermometer. Now add hotter water and use the VOM and thermometer to deside what tempature actually makes the switch operate. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

06-11-2002, 02:14 AM	#4
Jesse 67 c-10 Registered User Join Date: Feb 2000 Location: Edmonton, Alberta, Canada Posts: 599	The switch allows current through to turn on the relay, I'll try that with the boiling water, if it doesn't work I'll send it back, but maybe it will work after it clicks once in real hot water, I just don't want to get my engine that hot to see if it does! Thanks Jesse __________________ Edmonton, Alberta, 67 c-10, Long fleet, front disks, 5 lug rear end, 327 with Vortechs, edlbrock manifold, comp cams XE 256, 600cfm carb. Backed by a getrag 5 speed and 1 piece driveshaft. 1993 Dihatsu Hijet Jumbo cab 4x4, currently converting to battery electric power.

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