I have a goldwing 82 interstate gl and would like to know how to access the radiator cap. I can't see it through the fairing?

Walley, you may have to remove seat and false tank to access radiator and cap. Check the attached links,instruction and guides, Good luck
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Sit on the bike and turn the handle bars to the right. Look on the left hand side where the left handle bar was and you will see a rubber cap. Remove the left plastic cover panel around it and remove the rubber cap. It has hash marks to measure by. Ad 50/50 antifreeze till you see it half way up the hash marks. Be sure the rubber cap snaps back on tightly all the way around.If you ever need access to the radiator cap it is on the right side under that plactic cover. But you can add coolant on the left side. This is the upper level resivoir.

In between the radio and the digital clock you will see a key hole. Using the ignition key, this will unlock the raio cassette unit and you can pull the entire unit out of the fairing. There are no bare wires, only copper contacts. By bending each of the contacts at the rear of the unit out a little, you may have better contact when the unit is inserted again. The contacts do become compressed over time and this might solve your problem.

you should obtain the service guides for best chances, but it's not too hard on a gl1100.. I have the same motor in my gl1100i (82). There are links to downloadable versions of the manuals. Search for Steve Saunders Goldwing Forums... Then search within for the Goldwing library... If you have no luck, I'll post detailed steps to remove the radiator for a Honda GL100 motor, specific to 1981-1983.