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I just finished installing my new Dewitts aluminum radiator with twin Spal fans. It is one of the new ones where the temperature sensor comes already installed in the radiator and the radiator appears to already have a ground on it.

My problem is the fans do not come on by 210 degrees F. Before I start getting lectured, I want everyone to know that I discovered the problem after 5:00 on Friday and I have not had an opportunity to call Dewitts customer service.

I am not the greatest with electrical issues but this is what I think I know based on testing everything I could with my trusty multi-meter: The relays are getting power straight off the battery and from the accessory terminal on the fuse box. The mult-imeter also leads me to believe that the fans grounds are also good.

Can anyone offer any suggestions what to try next? How do I know if the temperature sensor is functioning properly or its signal is getting back to the relays?

Any help would be greatly appreciated.

Kelly
SW Florida

qwank

can you turn the fans on manually if you touch the wire going to the sensor to ground?

Shark Racer

There's a ground wire on the bottom of the radiator that needs to be bolted to a ground source. Did you do that?

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Are the fans supposed to come on when the radiator is cold if I remove the two wires off the temperature sensor and ground them? To answer your question, no. I did not know to try it. Back out to a garage full of mosquitoes!

Thank you.

qwank

yes, if you remove the wires off the sensor and touch them to ground the fans should turn on if everything is wired correctly. all the sensor does is act as a ground once it reaches temp

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"There's a ground wire on the bottom of the radiator that needs to be bolted to a ground source. Did you do that?"

No I didn't. The instructions don't mention grounding the radiator. On the radiator that I have, it appears that there is already a groundwire on it but it is just attached to the radiator and not the car. When I put the multi-meter between a hot wire and the groundwire on the radiator, it appears that it is grounded. But like I said, I really don't know if that means anything.

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qwank,

"yes, if you remove the wires off the sensor and touch them to ground the fans should turn on if everything is wired correctly. all the sensor does is act as a ground once it reaches temp"

Yes the fans come on when the wires off the sensor are put to ground. It is a beautiful sound at that!! So does that tell me that the problem is with the sensor or somewhere else?

0Tom@Dewitt

You need to attached that ground wire to good ground source. Scratch the paint off the area and screw it down. Then it should work fine

qwank

like Sharkracer already said

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Okay, I want to make certain that I am getting this right. Are we talking about making certain that the two ground wires coming off the fans are properly grounded or are we talking about attaching the existing groundwire on the radiator to the car?

qwank

the radiator needs to be grounded like Shark racer said. You know everything else works, so this has to be the problem.

remember, the sensor just acts as a switch that completes the circuit when it reaches temp.

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Thank you all very much for your support.

It still amazes me how much knowledge is available from the CF members almost as quickly as it is asked for. Ask a question at 9:30 on a Friday night and by 10:30...problem solved. Heck, I even got a response from Tom. Life is good!

I will ground the radiator tomorrow. The mosquitoes rule the night here in south FL.

Kelly

Kelly
SW Florida

vetteguy22

Hi Tom,
I would like to share some information about a recent experience I had with your company. As a private business man myself, I would want to know about these things.
Thanks,
Rob

0Tom@Dewitt

Feel free to email me any time

tom@dewitts.com

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HELP!!

Well the mosquitoes are down to an acceptable level and I can go back into the garage again. As instructed above; To ground the radiator, I disconnected the single ground wire where it was attached to the bottom corner driver side of the radiator and re-attached it under the head of one of bolts for the sway bar bushing bracket after wire brushing the bolt head and bracket. The fans still did not come on. I retested the system by grounding the temp switch wires and both fans came on again.

I then ran a hot wire from the battery to my multi-meter and grounded the meter to the same sway bar bracket bolt and got a 12V reading. By doing this does it verify that the ground is good for the radiator too? Like I said, when it comes to electricity all I can do is try to follow the directions. Any suggestions on what to do next?

Shark Racer

Did you get bare metal in the spot you grounded the radiator to? and I'm assuming the ground wire is still attached to the radiator, right?

What happens when you're at temp and you connect the ground wire to the source you're using for a good ground?

noonie

Might be easier to use the ohm meter portion of your DVM. Most have a switchable tone that lets you hear it. You can then just easily test between any 2 point for continuity.

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Thanks Shark Racer & Noonie.

To bring you up to date; The last time I turned the car on and let it heat up, nothing happened until the temp gauge got up about 220 deg and I turned it off. Only then did I discover that both fans were running. When they came on is a mystery since I can't hear them over the car in the garage. The last time I had looked, neither were moving. They both continued to run even when I totally disconnected the ground wire from the radiator! I am waiting on it to cool down again but right now, they both go on when I turn the key on to Acc.

Shark Racer

If the temp sender is not original it could very well be reading high.

So it sounds like it's working?

You do want to have the ground wire hooked up. Pretty sure it's there for the fan as well as to help with electrolysis.

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Well, working in the sense that both fans are coming on now. As of now, I have not seen just one fan running at a time. They both have been on. And, they appear to be coming on once the temp, as measured in the in the heads, is above 210 deg F.

The temperature sender (switch, thermostat...whatever) is the one that DeWitts installed in the radiator before shipping it to me. I was wondering if it was reading low and that is why they were not coming on until it was getting hot. And, I agree, I do want to have the radiator grounded.

I am waiting on it to cool down so I can start over again and just stand there and watch for when the fans come on. The problem is that by the time they come on the carbon monoxide has built up in my system so high that I forget why I am staring at it. I will post again in a while when hopefully I will have a bit more information.

At least it looks real pretty while I am standing there staring at it! Now that is serious progress.