Not to my knowledge. I've never seen a test for that. But then again I've never looked. If anything it would just activate the GPR. A volt / ohm meter would be more appropriate to test the GPR and GP's.
The 96-97 (at least the 97) Cali trucks PCM does monitor the two sides of the engine separately in regards to the GP's. Again I don't think there is any test capability.
That's what I figured. I think on the Cali trucks the PCM will throw a code if a glow plug draws less than 20 amps, but I'm not 100% sure. If anyone knows different please let me know. Thanks for the reply.