Heating and a/c lights flashing like a strobe light.

[72timemachine]

Hello,

Just as the title suggests, "sometimes" when I have the dashboard lights on in my 1990 c2500 Chevy, 5.7 liter, the climate control lights will flash very quickly like a strobe light. The lights which illuminate my gauges are not affected and work fine. I can also hear the engine's rpm over the music playing on the factory radio, I don't really mind that, however does that have to do with something in the ignition system?

If anyone has a remedy for this, would you please let me know. Thank you for any help.