Electric fan not working with a/c switch.. Multimeter help?!?

[bsturman92]

Alright so it's been a while now and I cannot get my electric fan to turn on since I replaced the radiator temp sensor with e36ti one.... Won't work at all and I wanna diagnose why,... Neighbor gave me a multimeter today and idkmhowmtomuse it.... Can someone start me in the direction I should go about solving my problem

[bsturman92]

Idk no to use it*^^ idk wat happened there haha... It's 91 318is btw... Worked perfect with a/c switch before now won't work for life of me

[808e30325i]

You gotta learn at least the basics of how electricity works to use a multimeter first. Knowing those things will help you better diagnose the problem.

[vpilarrt]

1) Pull the plug off the temp sensor
2) Turn ignition to ON, no need to start the engine
3) There should be +12V on the green/black wire (select DC Voltage mode on the multi-meter, put the positive (red) lead from the multi-meter on the green/black wire's contact and the black lead onto a unpainted metal bit of the car). If not, see 8
4) Short the green/black wire to the black wire
5) Cooling fan should operate on normal (low) speed
6) Short the green/black wire to the black/brown wire
7) Cooling fan should operate on high speed
8) If 3 or 5 and/or 7 doesn't happen you have a fuse, relay, or wiring issue
If they both happen either the temp switch is bad or coolant is not getting to the switch which would be because you're low in coolant or the system is not bled properly

[bsturman92]

Thanks man I appreciate that a lot.. Finally someone just tells me straight up what to do.. Electrical work is not my specialty for sure lol.. Ima gunna do this tonight and hope I get some good results... One more thing. The wires u want me to short... They all have that plug on the end of them to go back into the temp sensor... To short them I have to cut and wire them together then turn the car back on? That will put direct power to the low or high speed depending on which wire I put together correct? Sorry to sound like a noob just wanna know how I can short them and still be able to plug it back in... I feel stupid for askin this but like I said.... Bryan+electrician= disaster lol

[Gregs///M]

Start by checking your fuses first. No point in doing all that troubleshooting if the problem is a simple fuse that's blown. I believe the fuses is #3 15A and fuse #18 30A.

There are also two relays that control that fan. They are the orange relays and their location can be found in your owners manual. With the ignition on, they should click when you remove from the socket and click on when you plug it in.

When shorting those wires be sure to use heavy gauge cable. Using a little thin wire on that 30A circuit will melt in your hands and burn you.

[vpilarrt]

When I say "short" I mean take a 4" or so length of a piece of wire , strip the ends, put the ends in the sockets of the plug. You don't need to cut any of the wires.

Yes, the steps I described will apply power to the fan.

[bsturman92]

All fuses are fine and all grounds look good checked those already...not complete noob just don't know how to hunt for electrical issues..... And ur sayin with ignition on just pull one at a time of the orange relays and when I plug them in I should hear it click....... And to short the wires... How EXACTLY should I do that? Wire the green/black 12v to the high speed or low speed.. Cuz if I cut them I can't plug it back into the temp sensor

[bsturman92]

Oh ok I gotcha^ so when I short them don't eve mess with any of the three wires? Get my own wire. Strip the ends... Then plug them into the sockets on the temp plug... Just set the three wires aside while I do that?

^haha I'm a re-re u can only put wires into the plug not the sensor.. Jesus

[bsturman92]

Oh shit my bad man I get it.. I'm sorry.... The plug that has the three wires... Shit bro duhhh makes sense.. Ok I'll do this tonight and let u know how it goes... If fan turns on my switch it bad?

[bsturman92]

Ok so I jumpered the wires and it works! That means bad temp switch in the radiator correct? Buy a new one and hope it works? Even though this one is brand new

[bsturman92]

never mind...... i wired up the fan and hit the a/c button and turned on for about 6 seconds then shut off..... i jumpered the wires and nothing happened.... so then i left my car on while unplugging and plugging back in the relays and neither high speed nor low speed clicked.... whats this mean?