Radiator Fan not Starting

kiasta

New Member
I recently had an issue with overheating and it was due to the radiator needing to be replaced. I replaced both the radiator and the thermostat, flushed the coolant and all that. I'm not entirely sure if the fan started before I replaced the radiator, since I didn't check.

The fan works, I hooked it up directly to the battery and it started just fine. I tested the relay switch with a multi-meter and I was getting power. I was, however, not getting power to the plug that goes into the radiator. I wasn't getting anything. What would be the problem? The wiring? I don't know how because the wire that connects to the fan is also connected to the headlights (from what I can see?), which both are working.

I'm not a mechanic, so I am stuck at this point. I could just take it to a mechanic and have them do it, but I would much rather learn on my own. I'm still waiting on the Honda service manuals so I'm not really sure what else to test from here. Any ideas of what could be the problem?
 
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DavidR

New Member
5+ Year Member
Maybe a problem with the fan switch, its located on the thermostat housing, it should have continuity once the coolant temp is around 200*. Check with your ohm meter. Hope this helps.
 


kiasta

New Member
DavidR said:
Maybe a problem with the fan switch, its located on the thermostat housing, it should have continuity once the coolant temp is around 200*. Check with your ohm meter. Hope this helps.
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After doing more tests, you are right. It can't be anything else than the temperature switch. I shorted out the temperature switch plug and the fan started right up. I just did a drive around and revved my engine hard for a good 10-15 minutes. Coolant was foaming from the reservoir (that's a whole other issue, I don't think I properly flushed the coolant) but the fan was still not active. Before when I tested the temperature switch, I just checked voltage to see if power was coming through which it was but didn't know that I could just short it safely and check that way. I knew I could do that but I didn't think it would be safe until reading more about it, I'm still new to this DIY car repair stuff.

I'm glad it's not the electrical wires that would be a huge pain in the ass. But I have a question about the coolant, to anybody who has an answer. Well I guess I should give some back story on the car first. I just recently purchased the vehicle from some guy on craigslist and had the car checked and had some shop do maintenance. The water pump, timing belt, plugs, oil and fluids were either flushed or topped off (or so they said, I'm beginning to doubt they flushed any fluids, but I can see the water pump was replaced and the plugs, so hopefully they did actually replace the timing belt, but that's getting off topic). The mechanics apparently never checked the radiator because it was severely damaged. Anyways, I replaced the radiator and filled it with water and some radiator flush liquid stuff that I got from the car store, let the car run as instructed, and repeat. I did this 3 times minus the flush fluid, I did that only once. I found out that the coolant was foamy just just this morning. After driving it around, I put my hand on the reservoir cap to remove it and check the level but white foam was pouring out of the cap before I could unscrew it and it got all over my hands. Of course I jerked my hands away expecting the coolant to melt my hand, but it wasn't even hot, it was still cool. So what would cause the coolant to become foamy and leak from the reservoir cap? Should I just replace the reservoir as well?
 

Joe Mason

Respected
Registered VIP
Do you have a proper coolant/water mixture in the system now?
 


kiasta

New Member
Joe Mason said:
Do you have a proper coolant/water mixture in the system now?
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Well I'm using some coolant I got from the car store called Peak Long Life 50/50 mixture, not sure if that's proper but it was all the coolant they had. It's in a blue container and the liquid is green.
 

willost

New Member
Jump the thermo sensor on top of thermostat housing with a jumper wire. If fans come on you have a bad thermo sensor.

Sent from my SM-G920P using Tapatalk
 

kiasta

New Member
willost said:
Jump the thermo sensor on top of thermostat housing with a jumper wire. If fans come on you have a bad thermo sensor.

Sent from my SM-G920P using Tapatalk
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Yeah I did that yesterday and it started right up. I'm going to buy the sensor when I get off work and see if that fixes the problem.
 
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