Spal Fan Wiring To Existing Loom

[chipstick 382 1 Cars]

Would it be recommended to wire a Spal fan to the existing Peugeot fan loom?





I believe I could trigger a fan using my DTA S40 as an alternative - but my electrical skills are somewhat poor and unpracticed!

Any advice/threads/diagrams appreciated!

[cheesegrater 43 1 Cars]

I run a separate fan loom which consists of a 2 pin thermostatic switch operating the coil of a relay which it's normally open contacts control the fan, supplied straight from the battery.

[chipstick 382 1 Cars]

That's an interesting idea.

 

My battery is under the pass seat, but I have a distribution block in the engine bay.

 

Did you use a standard fan switch in the rad. I'd prefer to use that the add another elsewhere.

[welshpug 1,666]

that will run just fine on the original wiring, just need to find out which is which on the Spal fan.

[cheesegrater 43 1 Cars]

To be honest I went to ECP and asked them to find me a two spade m22x1.5 switch with my desired temperature rating. They can easily source them with that information. It's possible to use the standard switch if you know which pins they are not off the top of my head I can't remember which pin is high, low or ground.

[Miles 331 1 Cars]

If you've got a ECU that can run it then really it's a no brainer, 1 relay and off you go

[cheesegrater 43 1 Cars]

I also run a switched neg that bypasses the thermostatic switch so that I can over ride when the fan comes in but at the same time if I turn that switch off and the thermostatic switch is still made then the fan continues to run as a fail safe.

[chipstick 382 1 Cars]

Blue is the live and Black the ground.

 

I've given it some thought and decided to go down the ECU route as the capability is there so I may as well make use of it.

 

I've never wired a relay before but I'm sure with some guidance I shall work it out.

 

Luckily I have a Clio breaker outside so I pinched a relay holder and some wire from it. It was fitted with a 40A relay but I changed it for a 25A one I had kicking around from a 306.

 

 

The wire gauge may not be ideal?

 

Going by this DTA wiring diagram:

 

 

I can presumably use the fused 12v feed which the other relays in my setup use.

 

One of the red relay block wires tapping in to the 12V by the ECU and the other red wire going to the front of the car and the fan. One of the relay wires would go to pin 18 of the ECU. Is the other to be earthed and ran to the front of the car and connected to the fan earth and jobs a good'un? Again, the two thinner wires from the relay block really are quite small so should I source another relay block?

[chipstick 382 1 Cars]

In the end I made up my own loom as I didn't really want to extend those from the relay holder. I used insulated crimped terminals to join to the relay which probably isn't the best way to do it buy should be suitable enough.

 

Can I get it to work? No.

 

I didn't use the existing fused power feeds from the DTA loom as mentioned above in the end, I've ran a wire from my BMW battery terminal block in the engine bay, to a fuse an into the cabin where the relay is housed. I've then ran another positive wire back to the fan, fused the fan behind the headlight and inside from the relay I've joined to the earth which my ECU uses.

 

I've got power at the relay, and the fan will spin up if I ignore the relay and put power from the fused loom to the fan wire. So I'm confident all my earths are fine and the relay is getting power.

 

This is how I have wired it. Its a green 25a relay from a 306. Rather than the common 30,87 etc numbering it's 1,2,3,5 - which should be immaterial

 

 

What I'm not seeing is a reading from the ECU trigger wire when I put my multimeter on it. I'm putting my negative prove on the battery negative and the positive to the ECU trigger wire and expecting to see a reading which I'm not.

 

I'm also concerned about how I've adjusted the setting on the laptop. I've reduced the trigger temperature to a point where it's lower than my water temperature reading and still nothing. When I adjust it and get out to save, I do get the error 'MAP not transfered correctly' despite the new reading showing as changed. Perhaps the ECU is retaining the default trigger temperature? I forget what this is, but despite a drive and long idle on the drive I can't make it kick in.

 

If anyone could shed some light on the ECU trigger side of things and could tell me why I'm getting this transfer error if be grateful.

[jackherer 543]

The ECU trigger wire will switch to earth, not 12v.

[chipstick 382 1 Cars]

Thanks Jack. I assumed that hence the negative probe of my multimeter to the negative of the battery and the other probe to the wire. Is that not the way I should be doing it to check? I did similar but with a continuity setting to the negative terminal and it didn't beep as I'd hope it would when the setting was reached.

[jackherer 543]

Put the positive probe of your multimeter to the positive terminal of the battery and the negative probe to the fan output wire from your ECU and you should see 12v when the ECU triggers the fan.

 

What ECU do you have?

[jackherer 543]

This is what you need to do:

 

[Tom Fenton 1,548]

Agree with the above.

 

Also spade terminals onto a relay will work but isn't a nice way! Relay bases are very cheap and mean once done you can never get the wires mixed up.

 

http://pages.ebay.com/link/?nav=item.view&alt=web&id=140938481502

[chipstick 382 1 Cars]

It's a DTA S40. I've done as suggested with the multimeter and the reading goes from to 14 odd volts. I believe my issues with the temperature adjustments not saving is because I'm using a USB adapter and it doesn't like it. Annoyingly the fan is left set to kick in at 30 degrees.

 

Ta for the link Tom. I'll get one of those ordered and replace the existing.

 

Thanks for your help so far guys, greatly appreciated.

 

 

To clarify the amended diagram, I'm assuming I don't need the earth wire to chassis going to pin 2 where you've blanked it out - because the ECU trigger will become the earth and complete the circuit when triggered?

 

So do I need another positive feed added to pin 2? When I put a piece of test wire from the battery to that pin it kicks in. I'm trying to get my head around why there would be two 12v inputs.

[chipstick 382 1 Cars]

I've been googling relays with 2 feeds and I've learnt all about converting negative output relays to positive and so forth. Was something I never realised existed until you mentioned it.

 

I'll add a wire and fingers crossed I'll be able to eventually amend the map properly if I can make this USB adapter stable.

[Tom Fenton 1,548]

You are making this much more complicated in your head than it is.

 

All a relay is, is an electrically operated switch that can handle higher current.

 

To make the switch close (4pin normally open type relay, very common) you supply the coil with 12v on one side and earth on the other. It does not matter which way around.

 

When you complete this circuit the relay closes the switch. So what ever is connected to the switch contacts is turned on. In your case it's 12v from battery one side, fan the other. The fan will still need it's other cable earthing to complete the circuit.

 

Your ECU as per most if the others gives you switched earth outputs from it's programmable bits. So it provides the earth to switch the relay, you provide the 12v. Easiest way is as per the diagram above, bring 1 fused 12v wire to the relay then split it into 2 to feed both the high current switch and the low current coil.

[Simes 248 2 Cars]

I left mine as it was, the emerald can do it but it works fine and is completely stand alone.

[chipstick 382 1 Cars]

Your ECU as per most if the others gives you switched earth outputs from it's programmable bits. So it provides the earth to switch the relay, you provide the 12v. Easiest way is as per the diagram above, bring 1 fused 12v wire to the relay then split it into 2 to feed both the high current switch and the low current coil.

Did exactly that evening and all is well

 

 

That's another job ticked off the list. With all the messing about this afternoon I managed to flatten my little PC680 battery (well drained it low enough to not start the car) but I've only driven it once since I fitted it, which was only for 15 mins so hopeully it just needs a decent charge and will hold a decent charge for at least a couple of weeks. I will probably remove it from the car over the winter and trickle charge it, but it would be nice to think I won't have to worry about it too much with fairly infrequent use over the summer.