Fan relay won't shut off - Team Camaro Tech
Electrical & Wiring Troubleshooting electrical.

 
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post #1 of 8 (permalink) Old May 19th, 09, 07:57 PM Thread Starter
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Brad
 
Join Date: Jun 2004
Location: Kauai HI
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Fan relay won't shut off

I have an aftermarket fan relay jegs brand I believe. Its hooked up to a single fan. Set to turn on at 185. Cars been in the paint shop almost a year. I need to drive it home so I was getting all the lights working etc... and notice the fan was turning on when I was turning the key. Which wouldnt be a prob. except the car hasnt been started in a week. So noway the blocks 185 deg. Im mean its been getting hot around here but not that hot I checked out the wires on the relay traced them back and checked the inline fuse everything looked "o.k." Question is what do I check next?

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post #2 of 8 (permalink) Old May 19th, 09, 08:06 PM
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Pat
 
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Re: Fan relay won't shut off

well I've got the exact opposite problem...mine was set to come on at 200 and I cant get it to come on at all. Same deal too,power is good,fuse is good etc...nothing. Only thing i can think of is relay but its only a year old so maybe something with Jegs...let me know what you find
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post #3 of 8 (permalink) Old May 19th, 09, 08:28 PM Thread Starter
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Brad
 
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Re: Fan relay won't shut off

Mines only about a year too.

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post #4 of 8 (permalink) Old May 19th, 09, 11:35 PM
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Steiner
 
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Re: Fan relay won't shut off

Is it a fan that has worked correctly in the past?

If so, turn on the key so that the fan runs. Unplug the ground connection from the relay. If the fan keeps running, the relay has failed closed. If not, it is in the coil circuit. You need to now if it the coil completion is done by completing the ground or the 12V lead and troubleshoot from there. If you have a meter, it is much easier to find out what is going on.

I had a Flex-a-Lite fan that had the control board fail. With everything correct, it just stopped coming on even with the manual override after a couple of years. Haven't run an electric since.

'69 Camaro
Dart 400-AFR 195-224/224 HR-Powerjection III TB with F.A.S.T. Sportsman XFI
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'02 Z/28 vert-stock-sold and totaled
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post #5 of 8 (permalink) Old May 20th, 09, 07:51 PM
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Re: Fan relay won't shut off

Sometimes cheap relay contacts can weld themselves together when subject to high currents. You probably should put a volt meter on the coil leads of the relay to see if it is in fact energized. The other possibility is that the relay is miswired. Most relays have a normally open and normally closed contact. If you happened to get it backwards, the fan would run all the time until you reached temp and then shut off.

BUT, typically the relay is supplying battery power to the fan when an IGN source and temp switch energize the relay. The fact that you say it comes on when the key is on is sounding like a wiring problem ahead of the relay, or a bad temp switch. Hopefully you don't have your relay powered by an IGN source. That's a lot of current for an IGN supply to handle not to mention the load on the IGN switch and wiring.

Dave
========================
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post #6 of 8 (permalink) Old May 21st, 09, 11:44 PM Thread Starter
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Brad
 
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Re: Fan relay won't shut off

I got the car home today was able to fool around with the relay. From what I can tell its wired correctly and it didnt shut off when it got up to temp. Its just running on and on! What I did was disconnect the sender wire, the fan didnt turn on. I ground the sender wire and the fan turned on. So what do you think Dave bad sender?

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post #7 of 8 (permalink) Old May 23rd, 09, 03:31 PM
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Ron
 
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Re: Fan relay won't shut off

For one thing; NEVER use a Thermal Bio Metallic SX to source your 30 to 50 AMP FAN with our Old Rides and expect Digitial Components to survive.

NEVER use the Thermo SX to Control a 40 to 75AMP FAN Relay without Diodes across the relay coils to protect Mosfets and any other Transistorized Circuits including your CDI. Remember you are amalgamating Old Tech with Transistorized Circuits.

If you don't take DIODES into consideration you WILL burn out the transistors in your CDI Ignitions, DVD Players or any Modern Circuits you append to our rides.

Our Enemy is EMF Voltage spikes that relates to a 600 Volt Milli-Sec Spike to the system when a Relay Shuts Down and will Burn out our MSD, Mallory or Accel Components or a DVD Player. Just how many relays are in our old Wiring Systems that are not Diode Protected = NONE - Other then the HORN RELAY which does not control an Electrical Motor.

It wasn't until 73 that this technology was implemented in to Auto Wiring.

Use the Thermal Bio-SX to engage a 75 AMP Diode Relay to turn the Rad FAN ON & OFF; thereby using low current through the Bio-SX and Hi-Current through the Relay.

I've learned the Hard Way an studied Digital Fundamentals 101 ;o)

Read post RE: https://www.camaros.net/forums/showthread.php?t=158081

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Last edited by Z15CAM; May 23rd, 09 at 07:17 PM.
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post #8 of 8 (permalink) Old May 23rd, 09, 07:38 PM Thread Starter
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Brad
 
Join Date: Jun 2004
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Re: Fan relay won't shut off

I feel like I did something wrong I just was wondering if anyone had a quick fix to my problem. I put the relay in via the insturctions its worked fine till it was in the paint shop for about a year and now theres all kinds of gremlins. Ill get to each one of them. I havnt had the car for a year so I forgot how to find time to fool with it. Thanks Brad

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