RX-7tII88

iTrader: (1)

Thanks for looking. I have had the taurus 2-speed fan for a while now. I've had it wired always on with a Nissan relay I pulled at the junk yard. The fan was working fine in this configuration.

I recently bought this 30 AMP thermostatic controlled relay kit from Summit racing LINK

I have it wired as the directions show (including option ground switch) except that between the relay and fan I wired this SPST toggel switch to manually control fan High and Low speed
See the attached JPEG to see how I have the toggle switch wired.

ISSUES:

The fan will not run properly. Only the low speed will attempt to come on, and it is very weak. Hi speed will not run at all. Same results if I bypass the toggle switch. If I bypass the circuit breaker the low speed will run normally, but the Hi speed will not run at all. Only if I wire the fan motor directly to 12V will the fan run properly on both speeds. I have tried numerous grounds, and cleaning existing grounds with no changes to results.

I have my battery relocated to the cabin storage bin with large wire (cant remember size) running to a terminal to power the main fuse box. Summit Circuit breaker is near Main fuses. Summit Relay, Ground, and Toggle switch all near main relays at front bumper.

Has anyone tried this summit kit? Does anyone have any idea what I might be missing, or what I can test. I have a mulit-meter, but I am not the brightest when it comes to electrical, so I'm not sure what to test

I appreciate any help or input

Akagis_white_comet

iTrader: (4)

The diagram is a little confusing, but I think I see what's going wrong here. First, let's start with what you have done correctly.

Pin 85: Thermoswitch & Manual On Switch wired in parallel (Ground when ON)
Pin 86: Fused Ignition Switched 12v+
Pin 30: Battery 12v+

As for what's wrong, here's the short and simple:
A 30 amp breaker isn't enough to feed a Taurus fan. My setup is fused for 50 amps, exactly like on the 3.8L Taurus. As for the On-On Switch (presumably a SPDT one), it would have to be a supremely beefy switch to handle the hefty current going through it that the Taurus fan pulls.

Replace the On-On switch with a second 5-pin relay as follows:
30: from Pin 87 on First Relay
87A: Fan LOW Speed
87: Fan HIGH Speed
86: Fused Ignition Switched 12v+
85: Manual ON switch (Ground when turned ON)

This setup will activate the fan on Low speed first, and then can be manually switched to high speed with the second Manual On Switch. Benefit is that the massive inrush current (which is immediately tripping your circuit breaker) from jumping to high speed is negated as it has to be turned on Low first.
And be sure to fuse the main power feed for 40 or 50 amps, Taurus fans are thirsty Circuit breakers don't seem to fare very well under the hood. This is due to their Temperature De-Rating curve. In short, their current capacity drops like a rock when they heat up. I had a 150A breaker on my Taurus Alt for awhile and it consistently tripped in 10 minutes or less when mounted under the hood, even mounted on the driver's side and with a heat shield too.

Maxi fuse blocks for car audio are cheap, or you can build one for Bolt-on fusible links with a plastic project box and some suitable M5 or M6 bolts and nuts

clokker

iTrader: (2)

Just to be contrary...I've been running an even larger Lincoln fan for years on 30a fuses with no trouble at all.

jackhild59

iTrader: (7)

Agreed. Taurus draws barely 25 amps on high.

I'm betting you have the wrong wires hooked up on the Taurus fan. I'm betting you did it with the switch. And that switch is only rated for 20 amps..

Other issues: what wire gauge are you using? You need at least 10 gauge.

Remove the switch and verify function on low speed. Repeat using high speed.
Comet is right on the circuit breaker temperature issue.

RX-7tII88

iTrader: (1)

Thanks for the detailed response!

I will have some time to experiment with it later today. I think my issue is a combination of the circuit breaker and toggle switch being inadequate. I do know the start-up draw for the taurus fan is pretty high, so that may be tripping the breaker. And the toggle switch is rated for 20 AMPs. All wire sizes used are listed in the wiring diagram I believe

clokker

iTrader: (2)

Ditch the breaker, put in a fuse.
Even the Lincoln's onrush current hasn't blown mine.

RX-7tII88

iTrader: (1)

Well, here are the results. With the Relay wired directly to 12V (no fuse or breaker) The low speed runs fine (11.8V load side of relay). When I try to run the Hi speed in the same configuration I get nothing but clicks from the fan motor. The load side of the relay will spike 3-6V then slowly fall off to 0V.. I'm not sure why. Seems like the relay isn't handling the Hi speed fan

Any ideas?

Akagis_white_comet

iTrader: (4)

Sounds like the relay is being pushed too hard due to the fan motor attempting to draw too much juice (due to age). What is the relay rated to carry? Most 'consumer' ones are 30A, which might be optimistic depending on manufacturer. I'm running mine through an OE Ford relay, then to a Volvo 2-speed controller. No idea what the Ford relay is rated for, my guess is 40A, but it does the job with no fuss.

Something I should mention is that it would be better to have the HIGH speed relay before the Low speed relay as follows:

Relay 1:
30: battery via 50a fuse
87: fan high speed
87a: to relay #2 pin 30
85: battery (can be key switched)
86: thermo switch & manual on switch

Relay 2:
30: from Relay #1 pin 87a
87: fan low speed
85: battery (key switched optional)
86: thermo switch & manual on switch

This arrangement means that high speed overrules low speed. If you want, I can build you a clever 2-speed controller with some beefy relays in it and some other useful stuff too.