Do you mean the technicians workshop manual, somewhat overkill for the lightweight home dabbler like myself, especially at $180.

Yes that's the one. I have them for every car I've owned, because that's the definitive source. You might be able to find the wiring diagram(s) you need online, or at the library. But automotive wiring has gotten so complicated, because of it's dependence on modules (computers), you'll probably find there are several circuits involved. That link that UT posted, describes the interrelation of the components pretty well, and some possible solutions to try, if you want to wing it.

Those manuals are only abridged copies of what the automaker already printed (sold by Helms). Generally, the wiring diagrams in the base shop manual are poor. Often wiring diagrams are sold in a separate manual. Those manuals cost a little more - and provide significantly more information.

Sometimes people sell CDs with copies from that wiring diagram on Ebay. Or a CD version is available for the European version of that model.

Any repair shop has that same manual on DVDs that also includes the latest Service Bulletins.

Service Bulletins are also available for free from some County Libraries.

But there really is no replacement for a wiring diagram from the automaker and often sold by Helms.