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Fan switch

11994 Views 37 Replies 8 Participants Last post by  hossbuilder
My radiator fan started cycleing on and off and sometimes it wouldn't come on at all . When I wire it up direct , It runs fine . I have my fan running thru a relay , so I replaced the relay and checked all the related wireing and can't see any problems . I think I have the problem narrowed down to the thermostatic switch . I ordered a new one and will go from there . Has anyone else ever had a themostat switch go bad or am I the only one that has **** like the happen . Also does anyone know how to test one of these switch's . How about it Neil
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Jack,
I'm assuming that after you replaced the relay, the fan is still erratic. Attach another wire to the terminal on the thermostatic switch. Leave the original wire on. maybe use an alligator clip, or just wrap a wire around the terminal if you can. Make sure the wire is long enough to reach a known good ground. (hopefully the fan is cycling on and off erratically when the bike is sitting still, idling.) When the fan goes off when it's not supposed to, touch the extra wire to ground. If the fan comes on, the thermostatic switch is bad. All the switch does is provide a ground to the relay. You can test it by heating it in water, but that's a pain in the ass. Might just as well replace it. Good luck!! ............Don B
Jack,
I forgot to ask.........do you have 1 wire or 2 wires on your thermo switch? My original had 2. One to ground, on the block, the other to the relay. The one I put in has only 1, and that goes to the relay.......D
Thermo Switch

Jack,
I'm on my third switch NAPA Part# FS120. I don't know why they go bad. My son is going to see if there is a GM part that will be a direct replacement....Ray
Don , my thermostat switch only has one wire and it goes to the relay . Like I said , I replaced the relay and the relay breaker with new and it still acts weird so I have a new switch coming tuesday . I'm almost positive it's got to be that thermostat switch because everything else seems to be OK .
Jack,
I agree....Don B
X-Ray ,
I don't know why these switch's go bad , but when I went to NAPA to buy a new relay for my fan switch all they had to offer was one that is made in China . I wouldn't doubt that the FS-120 switch is made in China also. Does that answer your question ?
Well my fan switch problem is solved . I installed a new one and all is well again . I do carry a jumper wire so I can run the fan constantly if this were to happen again . Thanks for your help
Hey Jack,

Is that the original switch in yours that went south, or did you replace it with a different temperature unit??? Glad to hear it was only the switch.

Getting any riding in ?? Weather here is good during the week, crappy all weekend........go figure...........89 to 92 and cloudless in Vegas last weekend. Wished I had the Boss out there. For what I left on the tables I could have shipped it out and back :lol: And had no headaches :oops:

Tim
GRUMPY said:
Hey Jack,

Is that the original switch in yours that went south, or did you replace it with a different temperature unit??? Glad to hear it was only the switch.

Getting any riding in ?? Weather here is good during the week, crappy all weekend........go figure...........89 to 92 and cloudless in Vegas last weekend. Wished I had the Boss out there. For what I left on the tables I could have shipped it out and back :lol: And had no headaches :oops:

Tim
Tim

Sure wish I had known you were at Las Vegas this last weekend. Cozaey was at the Rio all the time and I went out to the Drag Strip. Worked our A$$ off and did fair but lost 2 engines and was out in the first round. At least we Qualified but had I known you were there, and if you wanted to, I would have put you to work on the crew. Could have at least had some adult beverages.

Adrian
Adrian,

Damned.......that would have been a blast !! We got in Friday morning and left Sunday afternoon, Vickis' boss takes us out once a year for a couple of days just to unwind..........hhmmmm 20+ years in the food/beverage industry, I would pick another "holiday".......oh well.

Maybe next time.

Sorry to hear about the motors.............gets pricey when they shell before you get into the money.

Tim
Actually this is the forth switch . The original switch was fan on at 165 , off at 145 . I didn't like it because the fan was running almost constantally . Then I installed a Painless brand switch and relay , on at 185 , off at 165 . I didn't like that so I kept the relay but installed a on at 200 , off at 185 . That seemed to work best and had that for about 2 years until last week it took a dump . The new switch I just installed is the same temp. range , on at 200 , off at 185 . With this temp. range switch , the only time my fan runs is if I'm stuck in traffic.

Vegas huh , wish I could afford to go there sometime . House goes on the market in a couple of weeks so we are busting our ass detailing every thing so it looks pretty . Still don't know where we are going , but have to take one step at a time . Am riding some but not as much as I would like . Oh well , once the work is done , it's time to play . Unless we decide to build a house and then the work starts all over again . We must be nuts.
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Jack,

What is the number of that switch? I think I may go that route once I get some miles on this converter. I want to wait and see what the temps do in the trans first, and I don't want to change anything else until then.

My engine has never seen the high side of 190 since I got it. Would be interesting to see if it changed the performance.

Good luck on the house/move. We're still not finished unpacking :lol:

Tim
Who knows why but I've had the Napa fan switch # FS120 on the bike for almost 4 years and about 21,000 miles without a single problem. Go figure! On at 195 off at 180...always and no malfunctions.
Joe
Hey Tim,
Ya'll having a heat wave up there in MN? 81 at 9:00PM!


Chris
Tim , I'm using PAINLESS PERFOMANCE PRODUCTS fan relay and thermostat switch I bought from SUMMIT RACING EQUIPMENT . The part number for the relay and switch is PRF-30102 . If you have the stock on at 165 and off at 145 , I can see why you have never seen higher temps than 195 , but I'll bet your fan runs allmost constantly in 85 degree weather . That's the reason I started experimenting because I got sick off the fan running all the time . With the on at 200 off at 180 , about the only time my fan runs is if I'm stuck in traffic and even then the fan won't let the temp get over 200 . Don't let anyone tell you you don't need a relay . Without one your asking for problems . I think Boss Hoss installs a fan relay on all the newer bikes ? Ya I know Joe , you don't have a relay and you have never had a problem . HA HA
Chris,

Wierd weather. It was about 70 degrees at 5 pm then by 9 pm it was 81. Vicki & I got the scoot out at 9:30 and it was gorgeous......just one of those strange weather patterns Barry keeps sending us. Still 79 degrees at 11:30 pm when we put it back to bed :lol:

Tim
Hey Jack,

Yup you're right. Rode 200 miles Saturday and another 100 Sunday.....
even with temps in the mid 80's I could only get about 160 to 165 on water temp. Fan ran all of the time.

But that was my reason for not changing yet, I wanted to see where the new converter would find it's temp range with no added heat from the motor. It ran all day between 165 & 170.....on time it got higher was after running on the highway hard and slowing in town for the first couple minutes with reduced air flow..........if that becomes an issue it would be easy to solve. So now it's of to NAPA this week to get another fan swith. I'm going to stick with something a bit cooler than yours, only because the nitrous prefers a little cooler set up.......but I think one like Eddie has may be perfect, 185 & 165. WIll have to see if I have a relay, but I think we do on the '03 bikes.

Still liking the converter, really don't know its there until you whack it good then it really livens up that small block. Saturday night with the bride on back it still spins with very little effort, even with the wider tire. Damend these things are FUN :lol:

Hows the house coming?? Man, knowing you, youguys will be building that house/shop next :cry: I'll be jealous.......

Say hi to Cheryl.

Tim
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Tim, I'm pretty sure you would have a fan relay on your 03 . Just look at your wiring drawing. I have a fan switch with a single connector for use with a relay on at 185 , off at 165 that I can send you if you want it .

House goes on the market Friday , but Cheryl wants a normal type live in house either new or not more than 5 years old . The garage I can have it any way I want .
Jack,

Hey I knew we'd find a trade somewhere :lol: I'll take that relay if you don't plan on using it.

Tim Brakstad
831 - Aspen Circle
Waite Park, MN 56387

Thanks.....

You going to stay on the water or go country??

We finally decided to go with a patio home, not exterior maintenance, yard work or snow removal. They do it all and we just go play when the mood strikes us. But then we kept the shop for the toys. It's a 3 mile drive to the shop, but it isn't all that inconvenient most of the time, and to find enough land to build a shop that size would have been out of the market area.

Some day when I retire I'll build a building and live in part of it, it just seems to be the perfect solution.

Thanks again and good luck on the house listing.

Tim
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