Radiator Fan Switch

Romeo85 · #1 (**permalink**) 04-29-2008, 06:37 PM

Ok so I was having some issues with keeping the temperatures in the cooling system down. After replacing the cracked coolant bottle cap I discovered that the fan was not coming on like it should be. So I ordered up a new unit and while waiting for it to show up in the mail I decided to remove the current one that was thought to be defective. Well I then discovered that the PO had cut the wires to the unit and looks to have wired up some kind of relay or something. I do know that the PO took the car over to Germany with him and so he told me that he had things like the headlights converted to euro spec so he could drive it over there, would this be something else that would be converted?

Anyone know what exactly is going on?
Couple shots of whats going on in the area

faitalfa · #2 (**permalink**) 04-29-2008, 06:53 PM

This looks like an aftermarket thermo switch. Does the coil part go to the Rad? If it is and is working you may be able to adjust it to get it to turn on sooner.

Hope this helps

CN

Romeo85 · #3 (**permalink**) 04-29-2008, 07:10 PM

Yea the wire goes to the radiator. The fan does not seem to go on at all. How would I go about changing when it comes on?

I would also rather just go back to how it should be from the factory.

jontg428 · #4 (**permalink**) 04-29-2008, 07:44 PM

You can check with Alfissimo (Jason) on this board. My car fan was not coming on at the proper time, working most of the time, but occasionally not coming on till 225. He set me up with a lower temp fan switch while I was in town visiting, car has been running nice and cool ever since.

**Richard2** · #5 (**permalink**) 04-29-2008, 08:44 PM

There's one of those switches on the 164B I bought. I'm not at all happy with it and bought an original switch to put in. I find it unreliable it works most of the time, but I've glanced at the guage and found the fan not on when it should be. I've had to change the setting depending on the outside temp. I just don't think it's very accurate.

Mike164S · #6 (**permalink**) 04-29-2008, 09:03 PM

You can get one from a '98 Passat. It turns low speed fan on at a little past the 175 degree mark. If I remember correctly it was about $20 shipped from rockauto.com

Romeo85 · #7 (**permalink**) 04-30-2008, 11:05 AM

Well the fan switch should be here today so Im going to look at rewiring the switch back and getting rid of the other non factory stuff. Would have loved to install the lower temp fan switch had I known about it.

Romeo85 · #8 (**permalink**) 04-30-2008, 04:49 PM

Fan switch installed. Got rid of that other part and the original harness plugs were still connected. Took the car out and got the temperature up to the line right after 175, brought it home to check if the fan came on. Well it didnt.

jontg428 · #9 (**permalink**) 04-30-2008, 05:12 PM

Check 45 AMP fuse on false firewall and make sure that it is good. Sometimes they can develop a hairline crack and not pass current.

**Alfisto Steve** · #10 (**permalink**) 04-30-2008, 06:07 PM

Quote:

Originally Posted by jontg428

Check 45 AMP fuse on false firewall and make sure that it is good. Sometimes they can develop a hairline crack and not pass current.

Romeo85 · #11 (**permalink**) 05-01-2008, 10:42 AM

Ok I found the 40a fuse right on the driveside of the firewall. Im not good with understanding electrical schematics and so how do I go about testing the fuse?

**Alfisto Steve** · #12 (**permalink**) 05-01-2008, 10:47 AM

Do you understand garden hose? Visualize battery as water pipe inside house and spigot on side of house as the 40 amp fuse bar that is turned on. now the juice is flowing to fuse and if fuse bar good juice flows through it but if it is shut off (blown) no juice gets through it.

Use a test lamp probe by touching terminals one at a time with test lamp ground wire grounded to engine or chassis. Both side of fuse should light lamp.

If you have a meter set it to DC volts attach black lead to ground and touch each side of fuse terminal nuts with red lead, you should have 12v both sides, if not check fuse bar for crack if only one side has 12v or lights lamp only on one side.

See this link: Troubleshooting 164 Cooling Fan System Part 1

Romeo85 · #13 (**permalink**) 05-01-2008, 12:31 PM

Ok I tested that amp with a multimeter. I hope I was doing it correct because both sides were only reading 7-8volts

jontg428 · #14 (**permalink**) 05-01-2008, 01:08 PM

Sounds very low, try jumping a wire between the two posts, only temporarlily, and see if the fan gets power then when at the proper temp. Also, measure voltage at battery, that is one heck of a power drop. Check back with us with the results.

**Alfisto Steve** · #15 (**permalink**) 05-01-2008, 01:40 PM

Stop do not jump across fuse bar. Unlock black fuse bar holder cover from G56 terminal board and retest for 12v at both large and small terminals which come directly from battery and see if you get 12v.

Be sure meter set on DC power and you ground black terminal to valve cover bolt or engine ground cable terminal bolt on chassis next to air cleaner. Touch red meter cable to both large and small G56 terminals one at a time to verify battery cables have 12v. Small one feeds 40A fuse bar.