wiring diagram

[bdriver]

Anyone have a wiring diagram for the radiator fan? I think that we have most of the wires in right but still are having challenges - burnt out two relays thus far.

Thanks

[trularin]

Need a 30 plus amp relay. Unless your fan has problems, this should cover the current draw of the fan. Painless makes a thermal circuit breaker type kit.

This means it will run until either the temp drops or the thermal breaker shuts the fan off.

JC Whitney sells a 70 AMP relay, but you will need to find a pigtail for it.

Hope this helps.

[Junket]

I belive Trularin is correct if you have two fans run two relays (one pulls too many amps for two fans ?) just hook the sending units & the switch legs togather on the relays.
Ken

[vettestr]

I have a generic sketch that might help. This will allow you to turn fans on with toggle sw. whenever key is on or will turn on automatic if engine reaches temp sw point and key is on. You will need a 20 to 30 amp relay for about 10 bucks and a normally open temp sw you bolt into block/water passage (mount near rear of block as it is higher there) at what ever temp you select. I use 170 degree and cost about 25 bucks in Jegs. This diagram is suppling B+ all the time key is on and using Neg. or ground to turn fans on via relay through temp sw. or you can turn on anytime with toggle. Be sure to use a fuse at 30 % above fan amp run rating and place relay signal gated by ignition sw.

[vettestr]

Here is a kit from jegs for 33 bucks and includes relay and thermal sw.
H764-30111 Replacement Temperature Sensor 185° On / 170° Off $32.99
go here for product
http://www.jegs.com//cgi-bin/ncommer...17&prmenbr=361

[bdriver]

Thanks guys - right now I have a 4 terminal relay that connects the dash switch, the amp meters by way of a fuse to the fan. Seems that the fan might be drawing a little too much power and is melting the fan motor relay connect -

vettestr - just order the kit...this ought to fix the challenge.

Thanks again.

[Rick Parker]

What gauge wires are you using?

[vettestr]

BDRIVER,
Warning bells went off in my little head reading about connection via AMP meter. If wired so current is passing through fan to supply amp meter instead of just using a leg of current source you could have problems.
It can be wired so only using as a tap but could also be wired so relay is passing all current to gauge and this will melt relay down.
Move wire suppling current to relay to any battery source to be sure or go point to point on wiring to verify how it was wired. Current or amps is different than voltage E=I/R . If you remove wire from relay supply and amp meter stops working you are toast..... This is a possible big problem or wire fire in waiting!!Must change to a voltage source only.

[Burnd]

BD:

The doubles drawww to much juice. My car was delivered with both fans wired directly from a toggle and the second fan MOTOR did a meltdown, (before the relay melted)! Wire the fans independently with no other instruments in the equation except the starter switch. I did starter switch to fuse box/relay to first fan and a second relay to thermoswitch to second fan. Second fan kicks in at 180 (little trial and error to get temp dialed in). Then I put an over-ride switch toggled under the dash which allows me to kick in both fans simaltaneously for hot day traffic, when the ignition is shut down. They're giving you good advice and the over ride switch is a comforting safety factor since your already crawling around in there anyway. Solder the connections. FWIW.

Bernie

[mylesdw]

Vettestr - I don't understand you generic wiring diagram. By my reckoning the ignition switch, the temp switch and the toggle are all passing the full current of the fans making the relay rather redundant. The relay coil is permanently live. Did I miss something?

[bdriver]

Jeff - thanks for the advise. No wiring fires yet but then again it's still early in my learning....

I might have oversimplified the wiring. I have four prong fan relay (lucus). This has one wire running to the fan relay; one wire that goes to the switch on the dash...two wires additional wire. One that goes to the horn relay and one that comes from the fuse unit. The other end of the fuse unit is connected to the ammeter...that line came from the starter soleniod switch.

All follows the wiring diagram that is on the Kirkham website (or so it seems) but is still generating so much heat that it is burning out (as in a hole in the regulator) where the wire runs from the fan to the relay.

What the battery source wire appears to be running from the battery to the starter soleniod to the amp meter to the fuse to the horn relay. Relay then runs to fan swith - and another wire to the fan...hmmmm.

Bernie - seems like a different lineup - your right about the connects - mine will work out.

Rick - don't know....hmmmm. These were the standard wire that came with the car - believe it's 12 gauge.

Bill

[mylesdw]

Can't help thinking something else is going on here. Is there any pattern to the failures? How quickly does a relay fail? Does it get hot straight away? Does it happen if you run the fan without the car's motor started. Is there a thermal switch anywhere in the circuit?
Sorry about all the questions, just looking for a clue...

[vettestr]

Hello Myles and Bill,
Myles the coil is redundant by design. The current draw of the coil in the relay is negligable but does allow the real current draw through a relay designed to handle the demands of 1 or 2 fans. The typical demand of 2 fans is in range of 15 to 25 ++amps and this is too much amperage for an ignition switch alone unless a special rated one for fans but why push it ? Relays are cheap and are designed to pass high current so just the right wat to go in my opinion. I do insist on soldered connections and often put a dab of RTV on nut holding wires so vibration not a factor.
If you forget to turn on a fan switch you can harm motorso redundant is ideal in this case. You may also want to turn on before temp sw for some reason so toggle is just nice to have.

[mylesdw]

Perhaps I miss read your diagram. I had assumed that your terminals marked in/out formed one pair (the contacts) and the ones marked +/- formed the other pair (the coil). Perhaps this is not the case?

That aside, your diagram still has the thermal switch and the toggle switch passing the full 15+ amps which especially in the former case must be marginal

[vettestr]

Hello again Myles and Bdriver
Myles
Your descrription of the 2 circuts is correct. The ignition sw is just gating or turning the relay on/off to supply current via the relay to fans. The current path via the toggle or thermal sw. is on the negative side of circut or suppling ground.
The current flow through either circut is in window of amp rating of each iand proper wire gauge is used. For high current demands of huge or big dual fans you could use thermal sw. to also gate a second relay on the ground side but I have not seen a failure with system described in drawing. I am saying you should use a relay to drive fans and not just the ignition sw. You must also consider the rating of fuses and switches when wiring fans. I like the second sw to control fans beside thermal sw but you could do without if desired. I do think using just a on/off sw without the auto function of the thermal sw is unsafe. What if somebody not familuar with car took her for a spin?
Bdriver,
If your system is stock from Kirkham site I am sure no problem their as everything from them is highest quality on anything I have seen. My concern was if fans became part of the series wiring of the amp meter by mishap or a late night field fix of some kind .
Lots of ways to skin a cat. This is just one I like and thought answered the question asked.

[bdriver]

Thanks for help and suggestions.

Jeff - while I fully agree with the professional work conducted by the Kirkhams - but the fan wasn't installed by them - so it is easy to have myself miss one wire and have caused something unexpected. It is nice to have received different points of view on the subject to allow me to take a deeper look into what I have wired. Clearly what I had wired is not working yet. Thanks again.

Bill

[Turk]

Bill,
Here is something else to check. I was stricking with intermittent fan problems las weekend myself. Ran a wire dirctly to the fan to see if it was the fan. It wasn't. Wondered about the relay because it was clicking bit not always. Stop short of replacing the relay (would have) if I had a spare.

Yesterday I discovered the culprit. The toggle switch!!

Made contact sometimes. Moving the toggle side to side revealed the contact was made not when it was flipped on, but when held toward one side or the other. Bad or burned out contacts.

TURK

[vettestr]

Turk and Bill and..
Thanks Bill, hope generic view helped and sometimes just movining wires or new install is the easiest route. I have often got stuck looking at same issue and can not see the forest for all the danm trees in my way. A short check here would be to remove wire at hot side of fan (when up to temp to make sure thermal sw is turned on if you have one). Be carefull with wire touching any thing and do not run long without fan working. Start engine now and see if the amp meter is still working. If fan is wired in series with amp gauge it will not work when wire is removed from fan. If gauge stops then rewire, if gauge works then keep lookin. Hook fan back up before she gets too hot.
Turk, The hardest problem is one that comes and goes. A cheap VOM is about 10 bucks and sometimes paying a bit more is the best. A Volt Ohm Meter with a high impedance is needed to check things like an 02 sensor cause the 10 dollar model will smoke a 60 dollar 02 sensor so whats a guy to do? The ground is always a problem on a glass car so verifing ground or resistance is often step 1. The cheapest meter will work here and grounds should be 1 to 10 ohms. Just checking continuity here will fool ya.
Have fun guys. jeff c