Electric Fan/Relay......Need some help!!!!

[rhodog77]

Hey guys,

I have installed a electric fan from skip white performance with a 50 amp relay. I have everything wired up but I can get the fan to kick on. The temp sender is set to open up at 200 and close at 185. I ran the motor up to 220 and still nothing. I thought that I had a bad sender so I spoke with skip white and they sent me another one. I installed it tonight and still nothing. My wiring kit is set up for both a relay and for a switch. I really want to stick with the relay but will run it with the switch if I have to. When I wire it to a switch, the fan works fine. The temp sensor is "ground seeking" unit. When the temp sensor reaches the preset temp the switch opens up and completes the ground which completes the relay to kick the fan on. Here is the issue, I know that the fan is wired correctly because when I disconnect the temp sensor wire and ground it to the motor or even to the pipe plug that the temp sensor is in...the fan kicks on like it is supposed to.

All I can guess is that the sender is bad or the sender is not registering the temp. I have it installed in the intake next to the water jacket. I dont know if installing it into the block somewhere will make a difference. Im pretty stumped at this point. If anyone has some tips or advice, I would really appreciate it. This is like the last thing keeping me from getting it on the road.

[ls1nova71]

If grounding the sender wire turns the fan on then it has to be the the sender. Are you sure the engine was actually above 180*, how did yoy verify it?

[Dan in Pasadena]

How about installing a ground strap from the engine to twhe frame, if you don't already have one?

[ls1nova71]

Originally Posted by Dan in Pasadena

How about installing a ground strap from the engine to twhe frame, if you don't already have one?

He said he can ground it to the pipe plug the sender is in and it comes on, so I would think its grounded.

[dwcsr]

What happens when you ground it to the body of the sensor? If it turns on then its the sensor. If not then you have to much pipe tape or sealer on the threads. You said it worked when you touched the pipe plug its threaded into so your motor grounds are fine. It is also possible that there is no water touching the sensor and it will not work without water touching the end.

Some times the spade terminal at the top gets twisted on installation and kills the sensor. This is the main reason for DOA sensors.

[rhodog77]

Then fan does kick on when I ground it to the body of sensor . This is the second sensor that I have tried. I thought the same thing about the fluid level not being high enough to register the sensor. I'm thinking about placing it in the block somewhere ,instead of the intake . I will probably swap out spade terminals is well
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[rhodog77]

Also my temp gauge seems to be in working order. I put a heat gun to the radiator hose and it was pretty close
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[RootBeer 6117]

Originally Posted by rhodog77

Then fan does kick on when I ground it to the body of sensor . This is the second sensor that I have tried. I thought the same thing about the fluid level not being high enough to register the sensor. I'm thinking about placing it in the block somewhere ,instead of the intake . I will probably swap out spade terminals is well
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rhodog, most of the GM temp sensors I have replaced have been in the cly head between the #1&3 cly there is a plug there for them.

[Russell Ashley]

If you have an ohm meter you could test the sender by putting it in a pan of water on the stove and bringing the heat up and see if it closes. I've tested a lot of thermostats and temp sensors this way. If you do test it this way remove it from the heat and let it cool naturally, don't dump cold water on it immediately.

Before I did that though, since you have two of them now, I'd just put one in the head where most Chevy's have the sensor and see if that doesn't fix the the problem.

[rhodog77]

Hey guys,

I currently have my temp gauge sending unit placed into the block between #1 and #3 cylinders. I think that there is one on the other side bewteen numbers 2 and 4.

Where do most people put the temp gauge sender. I have seen a bunch in the intake. Im hoping if I put the relay sender into the block that it will function properly.

thanks for the info. I think that I have a pretty good understanding how these sending unit and relays work. I just cant figure out whats wrong.

thanks again

[dwcsr]

Originally Posted by rhodog77

Hey guys,

I currently have my temp gauge sending unit placed into the block between #1 and #3 cylinders. I think that there is one on the other side bewteen numbers 2 and 4.

Where do most people put the temp gauge sender. I have seen a bunch in the intake. Im hoping if I put the relay sender into the block that it will function properly.

thanks for the info. I think that I have a pretty good understanding how these sending unit and relays work. I just cant figure out whats wrong.

thanks again

my temp sender is in one head and the fan switch in the other.

[OrrieG]

In my 64 chevelle the head location reads about 12-15 degrees hotter than the manifold did using the same gauge (VDO mechanical).

[rhodog77]

Orrie,

thats good info. I didnt want to ask a stupid question about water temp differing between the heads and the intake. I thought it would be the same.

dwcsr,

thats the route im going next. gauge sender in one head and relay sensor in the other. see if that works

[LDO]

Hmmm, my 283 doesnt seem to have any ports in the head. Could that be possible??

I have my guage in the manifold port and my fan sensor is in the water pump top pipe fitting. Havent run it yet. Hope it works as I am not sure what else to try.
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[tmoble]

yes, there's no plugs in the early heads, there should be a couple on the thermostat crossove passage on the front of the manifold. my 65 327 heads don't have these holes either.

you know, right, that the switch *closes* at the desired temp to provide a ground to the relay? if you ground the wire from the relay to the metal body of the sender it should turn on the fans. If it doesn't something is wrong with the relay or the wiring at the relay. Maybe the trigger/ground wire is on the wrong terminal?

[mr48chev]

Originally Posted by rhodog77

Then fan does kick on when I ground it to the body of sensor .
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If it doesn't ground out on the body of the sensor and grounds out on the pipe plug DW nailed as he usually does. Too much sealer on the sensor. The sensor has to ground to the engine to work.

[dwcsr]

Originally Posted by LDO

Hmmm, my 283 doesnt seem to have any ports in the head. Could that be possible??

I have my guage in the manifold port and my fan sensor is in the water pump top pipe fitting. Havent run it yet. Hope it works as I am not sure what else to try.
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You can use something like this
http://www.streetrodstuff.com/Products/1749/

[rhodog77]

guys,

i doubled checked tonight. the fan kicks on when I gound it to both the body of the sensor and the pipe plug in the block. The instructions I have say not to use any pipe thread on the sensor, whick I didnt. Its not leaking at all.

How can the relay be wired wrong if the fan kicks on when i ground out the sensor?? I guess I just dont understand these things. I have never been so frustrated with this project like I am new. Like I said the sensor is ground seeking, meaning that once the sensor reaches a certain temp, the switch opens up and completes the ground. Im going to drain the block tomorrow and install the new sender in the heads. If that doesnt work Im over it!!!! I will run the fan on a toggle switch and be done with it!!!

[LDO]

what is your reading when you meter from the terminal on the sensor to gnd?

I would think that it would read as an open right?

Have you tried placing the sensor in boiling water and checking your resistance reading then?

These things can really get under your skin but I'm sure with all of us here, we can figure it out.

[JPH]

Where do you have the brown wire on the relay connected if not using a fan switch?

[dwcsr]

usually if you ground out the relay switch wire and it comes on then the wiring is correct. When the wire is connected then you have 2 possibilties on why its not closing and grounding the relay and turning on the fan. 1. the switch is bad. 2. no water touching the switch to get it hot enough to close.

Put it in the head and if it works then it was the water not touching the switch, if it does not work then its most likely the switch.

Take the switch out. You can fab up a test station that we use here to test switches. if you have a toaster oven or regular oven use it for a heat source. take a car battery and connect the gound to the case of the switch. make a wire with a 12v light attached and connect it to the positive side of the battery and the top terminal.

So you have a circuit that comes from the battery positive to a 12v light to the top terminal on the switch. you also have a wire coming from the case of the switch to the negitive of the battery. to test the circuit take the top terminal wire and touch the case, if the light comes on then its wire correctly, connect the wire back to the top terminal and place the switch in the cold oven and turn the oven to 220* and wait for the light to come on. look at the oven temp thermometer to see what temp it comes on at. If its above the rated temp or does not come on at all then its bad and proven bad.

Don't try to boil water to get it to work. Its messy and a waste of time.

[ambryatim]

Originally Posted by rhodog77

Hey guys,

I have installed a electric fan from skip white performance with a 50 amp relay. I have everything wired up but I can get the fan to kick on. The temp sender is set to open up at 200 and close at 185. I ran the motor up to 220 and still nothing. I thought that I had a bad sender so I spoke with skip white and they sent me another one. I installed it tonight and still nothing. My wiring kit is set up for both a relay and for a switch. I really want to stick with the relay but will run it with the switch if I have to. When I wire it to a switch, the fan works fine. The temp sensor is "ground seeking" unit. When the temp sensor reaches the preset temp the switch opens up and completes the ground which completes the relay to kick the fan on. Here is the issue, I know that the fan is wired correctly because when I disconnect the temp sensor wire and ground it to the motor or even to the pipe plug that the temp sensor is in...the fan kicks on like it is supposed to.

All I can guess is that the sender is bad or the sender is not registering the temp. I have it installed in the intake next to the water jacket. I dont know if installing it into the block somewhere will make a difference. Im pretty stumped at this point. If anyone has some tips or advice, I would really appreciate it. This is like the last thing keeping me from getting it on the road.

Originally Posted by rhodog77

guys,

i doubled checked tonight. the fan kicks on when I gound it to both the body of the sensor and the pipe plug in the block. The instructions I have say not to use any pipe thread on the sensor, whick I didnt. Its not leaking at all.

How can the relay be wired wrong if the fan kicks on when i ground out the sensor?? I guess I just dont understand these things. I have never been so frustrated with this project like I am new. Like I said the sensor is ground seeking, meaning that once the sensor reaches a certain temp, the switch opens up and completes the ground. Im going to drain the block tomorrow and install the new sender in the heads. If that doesnt work Im over it!!!! I will run the fan on a toggle switch and be done with it!!!

Is it me or should it say..."closed" where he is saying open. In all my dealings with a ground seeking circuit....the switch actually "closes" when it reaches the set temp and "opens" when the temp goes down to specific temp. Are you sure you have the right switch?

Your switch should "close" (which provides the ground) at 200 and "open" at 185 causing the fans to go off. But, it will probably always run...depending on the thermostat and other factors.

It sounds like it is wired right....but, you have a switch issue....and it could be possible that you have a temp sensor instead of a temp switch.....I would just get one locally at Napa, Auto Zone, O'reilly etc....and if it does not work you can take it back instead of waiting.

I have a similar set up on my Blazer....I used a Taurus fan (2 speed) and wired it with 2 relays and a dual temp radiator fan switch....that kicks low speed on at 195 and high speed on at 210....the switch was from a BMW....and it is a grounding switch...works perfectly....I have my fan switch in the upper rad hose....I called Jags That Run and he made me an adapter with the exact threads that I needed. I will also be running a similar set up on my 57 but, with a Lincoln Mark VII fan.

Here is a way to wire it...http://www.s10forum.com/forum/f62/ta...4385...Post #9 but, on pin 85 of the relays I just ran 12v ignition power.....and none of the switches that he did....on pin 86 that is where I ran my radiator fan switch to provide a ground for the relays to turn the fan on......one for low one for high.
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[tmoble]

>>> Is it me or should it say..."closed" where he is saying open.

That's what I was trying to tell him in my earlier. He seems to have it backwards but I don't know if that's interfering with his diagnostics or not.

[LDO]

Placing the switch in a pot of boiling water and metering the switch wont work???
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[rhodog77]

Hey guys,

I see what your saying about "opening" or "closing". Maybe I was referring to it backwards. But even so, whatever you call it, its not operating the properly. I have had 2 or 3 people come over and look and the wiring. It is wired exactly like the above diagram.

dwscr,

thanks for sticking with this thread and dumbing down how to test my switch. I think I uderstand how to test it. I will give that a shot today. I am sooooo tired of draining the fluid out of my motor and then replacing it over and over and over again.

I really appreciate everyone chiming in on this thread. I dont want to let this little issue beat me.......Its personal now!!