# Rear defrost blows fuse instantly



## ziggirocco (Dec 13, 2010)

I posted this issue in the New Beetle section also, I have a 2003 turbo S and the rear defrost seems to blow the fuse as soon as you hit it, now the switch lights up red but never yellow as it would if working properly, I checked all the related fuses and the 1 fuse keeps blowing, if I prevent the #6 position on the switch from making contact then the fuse does not blow, the switch changed from red tom yellow when pressed, BUT I did not have time to see if the rear defrost gets power at the backglass.

If anyone has access to a wire diag, and let me know what #6 does on the car, or if you have ever had a similar issu?

checked all the wires at the switch and they all seem to get power and ground and light for the dahs etc.

I hope I did not forget anything

thanks in advance for any help.


----------



## johnywalnuts (May 27, 2008)

Fuses:
1 − 10 A Washer nozzle heaters, glove compartment light
2 − 10 A Turn signal lights
3 − 5 A Fog light relay
4 − 5 A License Plate Light
5 − 7.5 A Confort System, cruise control, Climatronic A/C, heated seat control modules, automatic day/night interior mirror
6 − 5 A Central locking system
7 − 10 A Back−up lights, speedometer vehicle speed sensor (VSS)
8 − − open
9 − 5 A Anti−lock brake system (ABS)
10 − 10 A Engine control module (ECM): gasoline engine 5 A Engine control module (ECM): Diesel engine, Model Year 2000 >
11 − 5 A Instrument cluster, shift lock solenoid
12 − 7.5 A Data Link Connector (DLC) power supply
13 − 10 A Brake tail lights
14 − 10 A Interior lights, central locking system
15 − 5 A Interior cluster, transmission control module (TCM)
16 − 10 A A/C clutch, after−run coolant pump
17 − − open
18 − 10 A Headlight high beam, right
19 − 10 A Headlight high beam, left
20 − 15 A Headlight low beam, right
21 − 15 A Headlight low beam, right
22 − 5 A Parking lights right, side marker right
23 − 5 A Parking lights left, side marker left
24 − 20 A Windshield and rear window washer pump, windshield wiper motor
25 − 25 A Fresh air blower, Climatronic, A/C
26 − 25 A Rear window defogger
27 − 15 A Motor for rear windshield wiper
28 − 15 A Fuel Pump (FP)
29 − 15 A Engine control module (ECM): gasoline engine 10 A Engine control module (ECM): diesel engine
30 − 20 A Power sunroof control module
31 − 20 A Transmission control module (TCM)
32 − 10 A Injectors (gasoline engine) 15 A Engine control module (ECM) diesel engine
33 − 20 A Headlight washer system
34 − 10 A Engine control elements
35 − 30 A 12 V power outlet (in luggage compartment)
36 − 15 A Fog lights
37 − 10 A Terminal (86S) on radio, Instrument cluster
38 − 15 A Central locking system (with power windows), luggage compartment light, remote/fuel tank door, motor to unlock rear lid
39 − 15 A Emergency flashers
40 − 20 A Dual tone horn
41 − 15 A Cigarette lighter
42 − 25 A Radio
43 − 10 A Engine control elements
44 − 15 A Heated seats


----------



## ziggirocco (Dec 13, 2010)

johnywalnuts said:


> Fuses:
> 1 − 10 A Washer nozzle heaters, glove compartment light
> 2 − 10 A Turn signal lights
> 3 − 5 A Fog light relay
> ...



no idea why you posted this, but thanks anyways, i need the wire diag, #6 is not the fuse no. it is the pin number on the defrost switch.


----------



## cuppie (May 4, 2005)

Hey, ziggi.

Electrical 101: in this situation, checking to see if power is making it to the rear window is, frankly, pointless. It can't be making it back there, as the line is shorted to ground (the reason that the fuse blows as soon as the circuit closes.

I'm guessing that it's f26 that blows, yes? 
Lacking in a wire diagram for that car, I did a little Googing. Looks like pin 5 at the switch is the feed from the fuse (should be hot with key on, and a good fuse installed), and pin 6 is (as you've surmised) the feed to the rear window. (reference) 
That it doesn't blow until you turn the defrost on says that the feed is fine, and the issue is on the load side of the switch.

Go disconnect the defroster grid. Check pin 6 for continuity to ground - it should be open (infinite resistance.) Anything lower, and it's grounded.
And, the single most-common failure point for wiring on _any_ car is in an area that the wiring moves regularly. In your case, in the area of the wire hoses for the hatch. 
Wiggle the wires there, with the meter (or test light) connected at the switch. Pop the hose out of the body & hatch. Wiggle. Take a look inside with a light. See anything? Any changes in readings when you do this?


----------

