I'm working on a Trane YCD240 RTU. this unit had been turned off for very long time 3+ yrs. Now customer need it. here is the problem
Unit got correct power going to it, turned it on. It will not do anything, nothing run. LED light on the control board lit up. Shorted Test1 + Test2 for test mode, but it will not do anything... Checked voltage across test1 and TEst2 got 1.9 VDC. (it should be around 5 vdc). Checked wiring, all seem ok...I'm guessing control board is bad... what do you think? need help..