Please help - Cavalier Fan N/W

[t-tim44]

94 1.8i Cav.

Just replaced t'stat, leaking rad and a seized fan but new fan doesnt kick in when its meant to resulting in overheating! I tried bridging the wee 3-pin connector that plugs into the rad as this usually makes the fan start but nothing happened. Is there a way to check if its the replacement fan thats fooked or some other wiring fault?

Thanks

[angryman]

When I was testing the two I've got here I just stuck a couple of wires from a spare battery on to the contacts........i think I've only got two contacts on these, can't remember and on the plastic bit for the plug on the fan it had + and - marked so you can't get the wires wrong

[t-tim44]

Cool thanks. I'll give that a go. Can anyone suggest what else might be wrong if the fan turns out to be working?

[t-tim44]

Can anyone suggest other faults that would cause the fan not to work about from dodgy fan itself? Its def not the fan switch/senor thing that screws into the radiator.

[dave's.cavy]

on a 1.8 8v, providing it hasnt aftermarket a/c fitted, it'll have just a 2 pin radfan switch and the rad fan but there is a fuse in the fusebox that can blow.

Other than that, there isnt anything else to go wrong in the circuit other than the wiring

[Giles]

remember it's a switched earth that turns the fan on. It has a constant live at all times.
So remember this when fault finding....

[t-tim44]

lol, my total lack of electical knowledge means i dont understand this much other than i rekcon its got a permanent live going to it? And the fan only comes on when the circuit to earth is completed by the switch? Which one exactly is the fan switch? Is that the jobbie that screws into the bottom drivers side of the radiator?

Thanks, sorry for being totally dumb on this issue.

[dave's.cavy]

lol, my total lack of electical knowledge means i dont understand this much other than i rekcon its got a permanent live going to it? And the fan only comes on when the circuit to earth is completed by the switch? Which one exactly is the fan switch? Is that the jobbie that screws into the bottom drivers side of the radiator?

Thanks, sorry for being totally dumb on this issue.

Yes, Yes and umm Yes

[t-tim44]

Ta

[t-tim44]

Update! I bought a multimeter today to try and help find this problem that's stopping the fan from working. I've taken photo's of how i tested it in hope that someone will let me know if i tested right and what the problem may be.

Heres the multimeter:



I set the meter to measure volts and put the earth part of the meter to the negative terminal on the battery. I bridged the terminals at the fan switch as shown in this pic. This normally gets the fans to run constantly for me but not at the minute! :



Then i probed the plug that goes into the fan. I put the red wire from the meter to the brown/white wire going into the plug:



And got a reading of 0.18 volts. I think this means there is power getting to it but its way too little to operate the fan? Did i test it right and is there some reason why there's so little power? I know the fan itself is definitely good. Please help!

[sparky33]

It's not that it's a switched earth, it's just that it's an open circuit, which is closed when a certain teperature is reached, this then completes the circuit. That is why usually bridging the wires turns the fan on.

[sparky33]

You nead to measure the voltage across the pins, not pin to earth

[t-tim44]

Which pins mate? The two pins in the plug that goes into the fan itself? I just presumed that one wire was an earth wire hence why i did one wire - earth. Should the voltage across the pins be 12v?

[sparky33]

there abouts, I don't know exactly as I'm not familiar with the engine.

[t-tim44]

Cool, so if it is roundabout 12v, then when the fan switch is closed (ie circuit completed when temperature reached) power is getting to the fan, yet it wont work?! I know the fan itself is okay. Not a fuse either as ive checked every single one lol. Me much confusedness (And not very clever lol)

[sparky33]

Have you tested the fan yourself?

[t-tim44]

Aye, plus did that continuity test and it was all good.

[sparky33]

test the resistance of the switch when the engine is cold and when it is hot to see if it is working.

[t-tim44]

Okay will do. Too late now, plus im on the Guinness so i'll have to do it tomorrow lol. I've a spare anyway if the switch is shagged.

[sparky33]

Well if you know the switch to be good, swap it anyway.

[t-tim44]

Spot on. Thanks for the help so far bud. Was a good excuse to try the camera anyway!! lol

[t-tim44]

Right, checked again today properly using advice from Sparky yesterday (Cheers dude). First of all i bridged the fan switch with a bit of wire as shown in the 2nd photo above /\. Then with the ignition on i tested the voltage across the two pins of that plug that goes into the fan as shown below:



I got 0v reading so no power is getting to the plug? Did i check that correctly? Next step i thought was to check if power was even getting to the fan switch plug so i took out the bit of wire that was bridging the terminals (even though its still in the photos) and put the meter across those terminals. 0v again:



No power getting to this plug either then? Iw as told if you do a continuity test with the meter, it'll beep if the circuit is okay and there's no breaks in the wiring so i linked the meter between the brown and white wire coming from the fan switch plug to the brown and white wire going into the fan plug itself and it beeped to say it was okay:



Did the same between the earth coming out of the fan switch plug (the top plug in the pic) and the battery to see if that wire was getting to earth and it beeped so its okay too.

Can anyone point out which fuse is for the fan?! :

[angryman]

Can anyone point out which fuse is for the fan?! :

Number 24

[t-tim44]

Good stuff thanks mate.

[t-tim44]

Do you know which one is the flasher unit for the indicators? It jams now lol. Cars a tw*t!