OK, spent some more time looking and did find a listing for a 1987 Jeep Grand Wagoneer, but no picture... so my kid is going to see if they have one in stock where he works at Oreillys auto parts.

Then someone may know how to test it with DVM?

They are CHEAP too! See if this link brings them up for you.
http://www.oreillyauto.com/site/c/searc ... vi=1182350