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Old 08-17-2007, 09:43 PM
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Please help! Radiator fan not working!

......Hi Everyone, the fan on the radiator on my '32 Ford isn't working. Here's what I did to trouble shoot it; 1) ran a hot wire off of the altinator directly to the fan & then ground the fan on the frame. The fan worked. 2) wired around the on/off switch on the dash. The fan didn't work. 3) Checked the fuse & it was good. 4). BUT I see that there is a relay box in the fuse box. I remember from my Firebird that there is a way to check the relays with an amp/volt meter, but I don't remember how to do it. My questions are; 1) how do I check the relay box. 2) for now can I just run the fan off of the altinator? 3) any other ideas on what it might be? THANKS Bill

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Old 08-17-2007, 10:29 PM
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Hey Bill-
I just installed a couple efans- so I know they can be frustrating when they aren't working right.
Personally, I wouldn't run the main power strait from the alternator. A better solution would be to run the main power from the junction block (terminal block) on the firewall, with a proper fusable link.

You say you have a relay on the fuse box- Is that specifically for the fan, or could it be for something else? I would check your relay wiring, and your ground connections. Relay should have a 12v switched power source, your main power wire in, power wire out to fan, and ground.
I wired my relay's ground wire to a switch on the dash. There are some good threads on here with relay wiring diagrams. Or check out Horvath's site- he's got some good info on there.

Good luck,
Nooj
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Old 08-17-2007, 11:36 PM
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Quote:
Originally Posted by billsbird
......Hi Everyone, the fan on the radiator on my '32 Ford isn't working. Here's what I did to trouble shoot it;

1) ran a hot wire off of the altinator directly to the fan & then ground the fan on the frame. The fan worked.

2) wired around the on/off switch on the dash. The fan didn't work.

3) Checked the fuse & it was good.

4). BUT I see that there is a relay box in the fuse box. I remember from my Firebird that there is a way to check the relays with an amp/volt meter, but I don't remember how to do it.

My questions are;

1) how do I check the relay box.

2) for now can I just run the fan off of the altinator?

3) any other ideas on what it might be?

THANKS Bill


Doc here,

FIRST of all..NEVER wire anything directly off an ALTERNATOR.your inventing and inviting tragedy..least of which the engine may NOT shut down with the KEY anymore..ALWAYS go to a FUSED , PROPERLY GAUGED wire buss. (Even for testing).

Second, the power and ground circuits are whole if you got fan operation with direct wiring, so you can eliminate that...HOWEVER, double check the ground at the radiator frame mounting, it may be poorly bonded..be sure it is at the SAME potential as your ground buss system that YOU installed.


UNLESS you know FOR SURE....

NEVER wire AROUND or through the temp switch (Assuming your's is temp sensed on/off automatically, most are..) senders...with POWER!! Traditionally, these operate off a ground from the engine block, to the relay coil GROUND (not power) to energize the coil at a specific temp...by adding power, AT or ABOVE that temp is nothing more than running the starter cable to ground..a DEAD SHORT..DETERMINE which yours is BEFORE proceeding..or your damage parts.


The most easy way, quick and dirty..to test the system, is locate the TEMP SWITCH sender..run the engine to 190 or there abouts..then jump across the temp switch with a wire or screwdriver..If the fan starts..you have a BAD TEMP SENDER SWITCH..replace as needed.

IF it does not start..then go to the relay..

BE SURE you know what you are looking for..sounds like this is another harness in a deuce..if I'm correct..and the buss MAY ALSO have a HORN relay, and High Low beam relay as well as flasher relays and a Choke/Charge relay that all look the same..If this is the case with yours..pull them out, and check the "footprints" If they are standard Bosch automotive relays, they will be the same on pinout (unless yours are for special purposes). IF they are interchangeable..pull them, While marking them, 1,2,3,4 etc..retain a known good one, and with all loads and power ON and the engine up to temp, plug it into the sockets one at a time..note what starts running..then move on until you find the fan motor starts...If that occurs, that (the one that came out that you numbered) is the offending relay. Replace as needed like $4 Fazools at auto~zombie..

If it's not working for you, or you can't find the problem, direct test the relays. Get a DVOM, Set it for OHMS Scale, RX1, Calibrated for "000", with FRESH battery's. Upend the relay. IF it is a standard Bosch type relay you will note numbers on the bottom next to the terminals..Those should be:
  • RELAY COIL # 85 = Power ( or ground makes no difference)
  • RELAY COIL # 86 = Ground ( or Power makes no difference)
  • RELAY TERMINAL CONTACT # 30 = Center wiper (movable contact)
  • RELAY TERMINAL CONTACT # 87 = Normally open contact stationary contact.
  • RELAY TERMINAL CONTACT # 87a = Normally CLOSED stationary contact.

Next get a 12 volt lantern battery, and a pair of alligator clips.

place your ohm meter probes across 85 and 86 you should read a RESISTANCE..IF not toss it the coil is bad..

Next, place your probe across the 30 and 87a terminals, it should read "000" , if not..toss it the contacts are blown..


Lastly, connect your battery to the 86 and 85 terminals, (polarity on the coil does not matter) you'll hear a "click". Measure the #30 and 87 terminals, it should read "000" IF not, or it does not "Click" toss it , it's bad.

you also have 2 sources of power to that relay...one to the coil The fuse you probably looked at..) AND a FUSE LINK to a # 10 wire coming odd the battery or battery source..to either the 30 or 87 terminal..check to see that is powered 24/7/365..this link is the most overlooked and common offender.

KEEP in mind......

An UNDER~COOLED engine is just as damaging as an overheated one....if you must run manual, do so for only a short time!!

Doc
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Last edited by docvette; 08-17-2007 at 11:42 PM.
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Old 08-18-2007, 02:06 AM
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.....Thanks Lumberjack & Doc, I made a mistake, I thought that I checked my horn fuse BUT it's in with my brake light fuse but doesn't say so. I keep blowing the brake light fuse when I hook up my fan so there must be a short, right??? Oh, I checked out my relay with my ohm meter & it tested good. I then took my horn relay & put it in the fan spot & the fan didn't work. To double check I then put my fan relay in the horn spot & the horn still worked. So my fan relay is good. My fan is not set up with an automatic temperature switch, I must turn it on/off manually. Also my fan ground is not wired straight to the radiator or frame but goes into a wire loom that runs under the dash. Tomorrow I will ground my fan straight to my frame. #2) take off my fuse box & check the hot wire fuse link & see if that helps.... Thanks again, Bill
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Old 08-18-2007, 06:17 AM
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Doc here,

Sounds to me like you have the FAN relay CONTACT TERMINAL #30 or 87, depending on how wired), ( not the relay coil terminal) connected to the brake lamp fuse..

AND.......

If that is the case, no wonder you are blowing fuses..brake lamps ONLY require 15 to 25 amps to operate and are gauged and fused for such..The fan can/Will pull anywhere from 40 to 75 amps on startup..

The RELAY COIL MUST always be wired to a switched Fused (about an amp) 12 Volt source, THEN the RELAY CONTACT wire that provides power to the FAN MOTOR when the contacts close, MUST be a 10 gauge, FUSE LINKED



or MAXI FUSE protected (about 50 to 75 amps) from the battery to the 30 or 87 terminal depending on how wired.









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Last edited by docvette; 08-18-2007 at 06:35 AM.
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Old 09-01-2007, 12:54 AM
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....THANKS Doc! , I just wired straight off of the battery with 10 gauge wire & used a fuse link to run the fan {for now}. BUT my problems got a lot worse so I'll re-post on another thread. Thanks again, Bill
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Old 09-01-2007, 02:05 AM
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Quote:
Originally Posted by billsbird
....THANKS Doc! , I just wired straight off of the battery with 10 gauge wire & used a fuse link to run the fan {for now}. BUT my problems got a lot worse so I'll re-post on another thread. Thanks again, Bill

Doc here,


I should bet they would...without a relay...

Good luck..post back and let us know..



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Old 09-01-2007, 02:49 AM
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....oh, problems not having anything to do with wiring. The Billet Specialties aluminum mount that held my alternator & a/c broke & this in turn put extra pressure on the alternator so the bottom mount broke off of it also. I sent the alternator & mount back to them & there replacing it for free but I want to get my car running in the mean time {the rental car is killing me money wise!}. Using the broken aluminum mount as a pattern I made one out of mild steel & put it on. But the alternator that I have is a 3 wire not a 1 wire so that's why the wiring questions....
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