Cooling Fan Resistor Details

[Mad Professor 7]

Hi All.

 

Can anyone tell me what the ohmage (resistance) & wattage is for the standard GTi Cooling Fan Resistor, for single or dual fan setup.

 

I know that each of the cooling fans draws aprox 10amps when running, and aprox 18-20amps as it starts.

So thats,

12v * 10amps = aprox 120watts.

12v * 20amps = aprox 240watts.

 

At this point in time I have a twin fan setup but no low speed, I would like to set them so thay both come on low and then goto high like they are ment to.

 

Thanks For Your Time.

 

Best Regards.

Edited May 3, 2007 by Mad Professor

[Super Josh 4]

Well if you've got a twin fan set up, then they don't use the resistor at all

They are wired in series to effect the low speed, so that will be half speed and then wired in parallel for full speed.

If you don't have the correct wiring and relay box, then the easiest way is to get them from a diesel model from a scrappy.

 

 

 

 

Josh

[Mad Professor 7]

Does anyone know how the dual fan system is wired.

 

I went upto my local scrapyard yestarday and thay now close at 12, and sods law I get there for 5 to 12

[Theo205 0]

Hello Professor,

 

If you use the 205 as a daily driver theres no point in using 2 fans no matter how hard you drive it.. If the cooling system is inefficient try replacing your rad with a good one.

 

I used to run high temps and installed a second fan (i live in a very hot country). The only thing that i managed is loads of noise when they kicked in at full speed, and the engine revs dropping from idle n (because of load). They did very little in helping to cool down the car because the real problem was the fact that I was using an inefficient radiator (clogged).

After I changed the rad I disconected on of the two fans and everything is ok now.

 

Now regarding the impedance of the resistor, i remember measuring it very low about 1.2 ohms( will go measure it later and confirm)

The problem is that if you will use these resistors for two fans connected in parallel you will be needing NOT 2 but 4 resistors...

 

The reason is that:

 

1)If you use 1 resistor for both fans the resistor wont take the load for 2 fans (twice as much current)

 

2) If you use 2 resistors in parallelyou will double the power handling of the resistor but drop the impedance of the resistor in half

 

A proper job is to use 4 resistors (2 in parallel 2 in series to maintan impedance and quadrable power handling) or find a ready made one of the proper impedance (which is very hard to find this low impedance of such high wattage)

 

Resistor should also be mounted on the chassis so that ther heat is dissipated to the body.

 

IMO its easier to either run your double fans at full speed or just repair your cooling system and run one a single fan with 1 resistor.

 

Theo

[Mad Professor 7]

I have a brand new TD Rad fitted, But as most peps on here know I am running a 1.9 Turbo Technics.

 

I have the dual fans but currenty only one is connected, and I don't have the low fan speed resistor, So only one fan kicks in on high at high temp.

 

This is not a big problem at this time, but when the weather starts warming up, and I start pushing the engine hard, I want both fans working how that should, as the last thing I want is the engine to start over heating.

[Theo205 0]

OK im sorry i didnt know you were running a TT setup.

 

In that case I would recommend to wire both fans in parallel and choose a rad swich for the exact temp you want the fans to kick in (so it wont start too late)

I think UK spec GTI are running 101/96-97/92DEG FAN switch. So if they are connected on the second stage of the fan switch they will kick in at 101 degrees.

If you want them to kick in sooner connect them to the first stage of the switch and they will kick in at 97 degrees.

Still if you want them to start at a different temp there are different models of fan switches at Pug dealer and you can choose the one you want.

 

Theo

Edited May 6, 2007 by Theo205

[Mad Professor 7]

I have now long brought a new fan temp switch 84-79c / 88-83c, I think this is the lowest rating one that peugeot sell.

 

Can anyone tell me if the dual fan relay setup uses standard 4 or 5 pin relays, or if it uses something else.

[Theo205 0]

AFAIK the fan circuit does not include a relay... It has nothing to do with the fusebox inside the car. Its fuse is in the small black box on the lower right of te engine bay on the slam panel, and that is where it gets power from.

[Super Josh 4]

The twin fan setup uses two relays, to switch the fans between series and parallel wiring. The relays are mounted in a large plastic box attached to the slam panel. Your best bet would be to get this box and wiring from someone breaking a 205 TD or from a scrappy.

 

 

 

Josh

[Rob_the_Sparky 9]

Hello Professor,

 

If you use the 205 as a daily driver theres no point in using 2 fans no matter how hard you drive it.. If the cooling system is inefficient try replacing your rad with a good one.

 

I used to run high temps and installed a second fan (i live in a very hot country). The only thing that i managed is loads of noise when they kicked in at full speed, and the engine revs dropping from idle n (because of load). They did very little in helping to cool down the car because the real problem was the fact that I was using an inefficient radiator (clogged).

After I changed the rad I disconected on of the two fans and everything is ok now.

 

Now regarding the impedance of the resistor, i remember measuring it very low about 1.2 ohms( will go measure it later and confirm)

The problem is that if you will use these resistors for two fans connected in parallel you will be needing NOT 2 but 4 resistors...

 

The reason is that:

 

1)If you use 1 resistor for both fans the resistor wont take the load for 2 fans (twice as much current)

 

2) If you use 2 resistors in parallelyou will double the power handling of the resistor but drop the impedance of the resistor in half

 

A proper job is to use 4 resistors (2 in parallel 2 in series to maintan impedance and quadrable power handling) or find a ready made one of the proper impedance (which is very hard to find this low impedance of such high wattage)

 

Resistor should also be mounted on the chassis so that ther heat is dissipated to the body.

 

IMO its easier to either run your double fans at full speed or just repair your cooling system and run one a single fan with 1 resistor.

 

Theo

 

Actually you put one resistor in series with each fan...you only need 4 if you do not seperate the fans until after the resistor. Much easier to just use 2.

 

However on a diesel it uses relays - probably the best way to do it as you avoid putting twice the normal load through the rad fan switch.

 

Rob