Hardtop rear window defroster resistance

Does anyone know what the resistance of the window heat element is supposed to be? I have measured 6.7 ohm across the pins on the plug but I think this is much too high.
I have never had an opportunity to use it but I would like to know if it works properly.

Thanks in advance!

Hello Jim,

the resistance is to high, about the cable dimesion and the 16 Amp-fuse expects a current between 10 and 14 Amps and a resitance round about 1 Ohm. I can´t measure on my hardtop due to a broken circuit, but it doesn´t matter, it´s hanging in the garage.

I think you have to check the surface of the contacts and the soldering in the contacts, furthermore the contacts (male and female side) direct on the windaow.

Hans,

Thanks for the information, this is what I was thinking as well. I did check the solder connections at the plug and they are ok. I have to decide if it is worth the risk of damaging the hardtop interior trim to investigate further.

Best regards,

Jim Oldham

Hello Jim,

that´s correct with 6,7Ohms you will have roundabout 2,1 Amps. At 14Volt are 30Watt "cooking".

If you have a power supply, you can measure the real current in the circuit and can decide, what are the next steps.

Hello Hans and Jim,

I'm having the same problem. I measure 11,7volts at the plug when the defogger switch is on, but I measure a resistance of 13ohms at the side of the glas window.

Is there a way to reach the connections on the "grid" without removing all the panelling/interior trim of the hardtop?

Greetings
Gunter

It looks to me that the inside trim will have to be removed. I don't know how the wires are connected to the grid on the glass. I have searched the internet for pictures but have not found any. According to the service manual the inside trim is easy to remove but I do not want to risk damaging it, especially since I do not need the rear defroster.

Hallo Gunter, the connections are on the passenger side of the windows. You have to take the lower outside chrom moulding off and you will see the connections in the bottom corner. The cable is routed through the frame from there to the front. There is no need for the inside paneling to be removed. I did all this when the glass was replaced.