1993 W250 Diesel.
Most of the time my truck is not charging. The A/C doesn't work. The overdrive and the cruise control do work. And if the CPS is bad then this isn't supposed to be how these things work. I say most of the time because they intermittently works as they should.
I do not have a scope to view the CPS sensor return, but it does get 8 volts, it does have a good ground, wire resistance is within specs (I believe it was 5 ohms) between the PCM terminals and the sensor connector. I do not have a DRBII to read the computer either.
According to the factory manual the CPS provides the signal for the PCM to turn on or off the Charging circuit, A/C, Cruise Control, and Overdrive. I am not 100% that this is accurate, however a couple of mechanics I discussed this with stated that they did also believe that this was the case. If the CPS is bad,
So, how do you test a CPS if you don't have a scope?
Why would only the two circuits and not all four circuits be compromised?
I suppose if the CPS is good, then logic would state that the PCM is bad.
Any help? Please?
Thanks in advance.