Wiring up a switch to the thermo fan?

[VNracer]

My fan isn't working in my VN. I found this out after a long period in traffic when the car heated right up. I already have a switch in my car under the steering wheel which was installed when I got the car. I was thinking that this may have been for the fan but it wasn't conected. I've heard about poeple wiring up a switch in the car to turn on the thermo fan, so i was thinking it could be running to the fan already and just need a wire reconected. (where would the switch conect??)

Any info would be great.
I've checked the fan fuses already and flushed my radiator.
I want to get the fan fixed and see if thats the only reason my cars heating up and that there arnt any therostat problems.

Don't know alot about Holdens or cars. Any info would be great (DETAILED IF POSSIBLE).
Thanks

[Benji]

yeah i would love this went to a skid pan day and by the time my fan cut in it was to late i realy need a switch so i can just activate it straight away

[calais_cruzin]

u can just wire it up straight to the batt if u dont know how to wire into the ignition.

All u do is cut ur cable for thermo, wire ur ground to body then run a wire from the thermo positive thru ur switch then thru a fuse then to the batt.

Those missle switches are the go i used to have cheap dick smith swithes n they eventually break from too high current.

Just make sure u fuse it, start small eg 1.5amp n work ur way up till she doesnt blow.

Its easy to do 45min job

If u do know how to wire it to ur ignition it would be better as u dont have to turn it off wen u stop if its running.

I just did mine to the batt just to save time.

[VNracer]

All u do is cut ur cable for thermo, wire ur ground to body then run a wire from the thermo positive thru ur switch then thru a fuse then to the batt. Is there any other wires than the ground and positive? Is there a negative wire?

The switch i already have may be broken and need replacing?
The wires from this switch are running to the fuses nd relays under the steering wheel? Is this where u'd wire it to the ignition?

Cheers for ya help

[Cheap6]

Perhaps this may help:

turning std thermo fan on with ecu and a switch

[VNracer]

OKay cheers guys, sounds easy enough.

Where is the ECU located?
I know where the fuses and that are.
thanks

[immortality]

you got it slightly wrong in the other thread. putting 12v volts directly onto that pin on the ECU could damage the ecu. the ecu switches the ground side of the circuit (negative) not the +12volts side. see other thread for correction. you'll still need to figure out why your thermo fan isn't working cause this mod utilises all the original factory wiring etc

[cracker]

theres a better way to do it then that, run an earth from...blue,yellow wire from the ecu to an earth hey presto fan turns on not 100% about the colour but cant quite remba

[ear099]

mate i tried this with my fist fan i wired it upto the ignition so it was all the time the fan lasted the whole of 2 days

run a wire to the fan fron the the cabing put a switch in and then earth the other side this is your negitive cable connect it to the earth side of the fan (black wire) connect positive (blue wire) to the battery and then when stuck in traffic turn it on and off with the switch just make sure that you turn the switch off when you stop the car

[Cheap6]

Sorry, misunderstood as to what another post was referring.

[Cheap6]

mate i tried this with my fist fan i wired it upto the ignition so it was all the time the fan lasted the whole of 2 days

run a wire to the fan fron the the cabing put a switch in and then earth the other side this is your negitive cable connect it to the earth side of the fan (black wire) connect positive (blue wire) to the battery and then when stuck in traffic turn it on and off with the switch just make sure that you turn the switch off when you stop the car

Apart from deleting the relay and thus requiring a heavy duty switch and cable, having to remember to switch it off, extra wiring and holes through the firewall, how is that different, particularly in terms of what the fan sees?

[Cheap6]

OKay cheers guys, sounds easy enough.

Where is the ECU located?
I know where the fuses and that are.
thanks

Immortality is correct in that you will need to work out why the fan isn't working. The link was intended to answer some of the other questions and provide you with enough info on how the system works to solve your problem yourself. Too hard to cover all the possible variations beyond that.


(The pins to the ECU are labelled by tiny lettering cast into the plastic terminal connectors.)

Extra added bit:

Actually, VNracer, you did ask for detail, so while I can’t cover everything….

Tools: A 50mm length of wire the same thickness as that to the cooling fan, with the ends bared about 10mm. A test light (or multimeter set to measure voltage).

Caveat: use any wiring colours as a guide only. They sometimes vary and I have a VP not a VN.

Ignition on “run“, engine off (red warning lights on dash lit).

Start at the cooling fan relay, under the bonnet.

Pull the cooling fan relay. On one side of the relay will be imprinted a small circuit diagram of how the relay works. It is simply an electrically operated switch, using a low current circuit (85,86) to switch a high current circuit (87,30) which the electrical load , in this case the fan, is on.

On the underside of the relay will be imprinted the numbers corresponding to the terminals. I find it easiest to hold the relay in position above the connector block to ID the wires corresponding to the pins.

On the high current, switched, side, terminal 30 is 12V+ from the cooling fan fuse under the bonnet. The test light when connected from this terminal of the wiring harness (orange/pink) to earth (battery negative or body) should now light.

Terminal 87 (orange/blue) goes to the fan motor. Using the short length of wire to jumper the terminals in the wiring harness corresponding to pins 87 and 30 should operate the fan. If it doesn’t, check there is 12V+ on the orange/blue wire at the connector closest to the fan with the test light to earth (with the jumper wire still in place). If that is good, use the other wire on the connector closest to the fan (black) as an earth instead of the battery negative or body. If the test light lights now, the earth is also good (at least at the low current drawn by the test light). Power in + good earth out = a dead fan.

If the fan and its associated wiring checks out as good:

On the low current, switching, side, 86 is 12V+ in from the ignition relay, via fuse 9 which is under the dash. (If the interior fan works, fuse 9 is OK). There should be 12V+ at this terminal of the wiring harness (pink/white). Check with the test light connected between that terminal and earth (battery negative or body).

85 is the ground/earth/negative side, in this case via pin C1 and the ECM (blue/white). To test this, put the relay back in, ignition off (to avoid the possibility of damaging the ECM while attaching jumper wires). Locate the diagnostic link (ALDL) above the ECM and jumper the black/white and black wires’ terminals together. They are at one extreme end of the connector. A paper clip may work better than the thick gauge wire here and Googling “ALDL AC Delco fault codes” will give a better description of the diagnostic link than I can. Ignition back on and the cooling fan relay (and fan) should audibly click, = “on”. The cooling fan is switched on by the ECM whenever the black/white and black wires are connected and the ignition is on. (This is also the diagnostic mode used flash the ‘check engine’ light and reveal fault codes).

If you do decide to wire around the factory system, save a lot of drama and match the factory system using a relay o

[VNracer]

OKay thanks for that, great help.
I'll have a run threw this and check out the wiring. Hopefully its just that.

Cheers, let you know what i find

[VNracer]

Okay i had a go at finding the problem.

Started off well with pin 30 & 87 both working, and when the jumper wire was in place the fan started.

I however didn't get any signal from on the low current, switching, side, pin "86" 12V+ in from the ignition relay, via fuse 9 which is under the dash

Any ideas? Cheers

[immortality]

Okay i had a go at finding the problem.

Started off well with pin 30 & 87 both working, and when the jumper wire was in place the fan started.

I however didn't get any signal from on the low current, switching, side, pin "86" 12V+ in from the ignition relay, via fuse 9 which is under the dash

Any ideas? Cheers

ok, so check to see if there is power at the fuse, pull the fuse and test with a meter, there should be 12volts at one of the fuse terminals. if there is 12volts at the fuse then you need to chek the wire going from the fuse to the relay. simply test between the pin from the relay (pin 86) to the fuse. testing usingthe continuetyfunction ofthe meter or use the resistance (ohms) test function. if there isn't 12volts at the fuse then you need to trace the wire back to it's source to see why?

[Cheap6]

Now we're getting there! I see that in another thread you mentioned that the blower fan was not working properly either so may be able to solve both problems.

One simple thing to try is to swap/replace the ignition relay, under the dash.

You can check the fuse as per your post Immortality with it in place using the slots on the top of the fuse. The 12V should be on both sides.

Worst case, if the fault is buried in the wiring harness somewhere you can run an extra wire out of the ignition relay, leaving the original wire in place if desired, directly to pin 86 of the cooling fan relay.

[immortality]

Now we're getting there! I see that in another thread you mentioned that the blower fan was not working properly either so may be able to solve both problems.

if indeed your heater blower fan isn't working as well as the thermo fan not working then most likely your fault lies somewhere in the wiring from the ignition relay to the No8 fuse which supplies +12volts the coil side of the engine cooling fan relay and also +12volts for the heater blower motor etc (i'm assuming there isn't a fault with the iginition relay as the engine does run, check light work etc)

[Vs_Esteem]

hi all i recently brought a vs commodore n the prev owner has hooked a wire from the cooling fan to the fuse box,instead of it being proper,i done a big drive from nsw to sa n had no trouble but driving in the hills its been getting hot and its noisy as cause i was told it is soppose to have two speeds not flat out all time,anyone know where it is soppose to be hooked up to ?