I need info on changing the coil. I purchased an aftermarket made by BWD. It says I will need an external resistor # 903. Also could anyone tell me where the
+ terminal is on the coil? Looking from the back of the engine forward, is the +
terminal on the left or right. A schematic would be great.

Thanks for any help.

Bill

 

What year, model, and engine?

You might not need a resistor at all.

Usually the coil posts are marked with a small "-" and "+"

Cheers
DD

 

Doug,

Thanks for the reply. The car is an 86 xj6 S3 base model.

 

On your car the coil probably has a ballast resistor attached directly to the coil "+" post. If it doesn't then the coil may have already been replaced (not unusual) or the ballast resistor tossed in the trash bin (not unusual).

If you have the original ballast resistor, and it isn't burned out, you can transfer it to your new coil. If you don't have the original ballast resistor I wouldn't worry about it. Plenty of owners dump 'em.

So long as you have a 12v coil with roughly 1.0 ohm primary resistance you'll be OK. The BWD coil you bought probably has this info on the box or paperwork.

The "+" coil post should be marked "+" and have solid white wires attached (or, as mentioned, an original ballast atached). It would be on the right side looking from the rear .

All of the other wires go to the "-" post. These will be white/black, white/slate/blue, and maybe one other color that escapes my memory at the moment.

Cheers
DD