Hardtop Demister question Help needed from auto elec. guru

[Troy_H]

I require the help of someone who have fitted an older style top to a NB. Ive read the miata.net instructions but am having problems.

I seem to have a problem completing the circuit so the unit switches on (the previous owner never used the demister so im unsure if it actually works)

The plug for the unit was damaged so needs a new loom. to avoid this, i thought i would just be able to join the wires to the existing soft top system. This appears to not be the case.

The circuit in the hardtop is fine with no broken wires.

Is the wiring system different to the soft to (perhaps the earth is different). I imagine i need to buy the NB hardtop loom to run the top on the newer model but only want to get this if i know it will solve my problem.

Any suggestions? about the way the system works or how i might be able to test of fix this situation.

And yes, i know i dont have to run the demister and that it clears with the air con, but as I have it on for 6 months a year, I may as well have the system installed and working.

Thanks
Troy

[Okibi]

Have you checked the fuse?

Can you check if you have a current with a multimeter?

[Troy_H]

Hi Okibi,

yep, fuse is fine, the soft top works no problems so current is going to the Hardtop, just doesnt seem to be completing the circuit.
so, I assumed the hardtop was to blame. I checked with a mutilmeter that the cirsuit is complete on the top and it it is.

Should be a pretty simple process, this is why im confused.

This has now got me wondering if the wiring is different for the hardtop.

Is the plug that you use to power the top just a positive wire with a return?

The plug that came off the opt had three wires, one in, one out and one that joined the line in that maybe goes to earth?

[Okibi]

I seem to remember the defroster automatically turns off if the soft top is down. I run my hardtop over winter here so i'm not 100% sure.

Perhaps it's thinking the soft top is down and therefor turning off the defroster wiring (that you're using for the hardtop)/

[Troy_H]

The hardtop has a plug that you would use, unplug the soft top one and plug this one in. I presume the wiring set up is different on this and it uses different wires on the connector to power it.

I think i may need to take a closer look at one that has it currently installed to see the difference.

Thanks for your help so far.

[Andrew]

I have the wiring diagrams for an NB somewhere.....

Troy, to have a PM.

[Troy_H]

Cheers Andrew,

that should solve my problem. Ill have to make some time to have a look through.

Much appreciated.
Troy

[Andrew]

No problem