Electrical Issue - TN65D

[Zoombah]

I have an electrical issue with my TN65D that has me stumped. One day all the cab electrical components worked; the next day nothing worked. I checked the large 50 amp fuse that feeds power to the cab fuse box. It looks fine. Now here's the stumper. When I plugged the 50A fuse back in the radio/CD player in the cab momentarily powered up and ejected the CD in it. I then turned key and tried turning radio on. It did not come on. Neither did the fan on the A/C unit. I then pushed the CD partially back into the radio and pulled and re-installed the fuse. The radio did the same thing when I re-installed the fuse....it ejected the CD. The fan did not blow at all.

I am stumped as to how the cab circuit can power the radio long enough to eject CD but nothing else works. Any ideas?

 

[dqdave1]

Any auto reset circuit breakers in line anywhere? Are the fuse connections good and clean?

 

[jinman]

When the CD ejects, push the tray halfway back into the player and release it. Does it open back up? If it is spring loaded to open, it only needs an instant to unlatch and the ejection is all provided by the spring. I'd look for a loose connection somewhere that is barely making contact. It might be a bad connector or broken wire. It sounds like you need to do some continuity testing while wiggling cables that feed power to the cab. You might get lucky and find it quickly.

 

[RickB]

When the CD ejects, push the tray halfway back into the player and release it. Does it open back up? If it is spring loaded to open, it only needs an instant to unlatch and the ejection is all provided by the spring. I'd look for a loose connection somewhere that is barely making contact. It might be a bad connector or broken wire. It sounds like you need to do some continuity testing while wiggling cables that feed power to the cab. You might get lucky and find it quickly.

Don't forget to check all the ground connections. In fact, if it were me, I'd check all the grounds first. Is the exterior lighting working? wipers/washer??

 

[Zoombah]

No jinman. As with all car radio/CD players I've seen the feed and eject is motorized. There is no tray; they suck CDs in and spit them out via a motor driven mechanism. The CD does not automatically eject when pushed back in halfway. But if I pull the fuse and re-insert it then the CD eject mechanism whirls into motion and spits the CD out.

RickB - I will look for a chassis ground from cab to chassis. Maybe I'll get lucky. A loose or bad connection as suggested by jinman would explain loss of power to everything fed by the cab fuse panel.

Thanks

 

[jinman]

No jinman. As with all car radio/CD players I've seen the feed and eject is motorized. There is no tray; they suck CDs in and spit them out via a motor driven mechanism. The CD does not automatically eject when pushed back in halfway. But if I pull the fuse and re-insert it then the CD eject mechanism whirls into motion and spits the CD out.

RickB - I will look for a chassis ground from cab to chassis. Maybe I'll get lucky. A loose or bad connection as suggested by jinman would explain loss of power to everything fed by the cab fuse panel.

Thanks

Well, the CD tray was just a guess. Like you, almost all I have seen are driven open and closed.

My wife has been having her clock reset and the CD player eject on her Venture van. Yesterday, she was in town doing some shopping and we decided to meet at a restaurant for dinner before going home. When we went to leave, her clock had reset and on attempting to start the car, everything went completely black. I told her to pop the hood. I wiggled the ground lead to the battery and the dome light came on. The ground lead to the battery was loose and dirty. I tightened the lead and all is now good.

I suspect you will find something similar with your cab. As RickB suggested, it could be a faulty ground. I'm not sure why it works when you remove and replace the fuse, but it sure sounds like a loose connection. Ground is definitely a good place to start.

 

[Zoombah]

Problem solved!!!

On a hunch I pulled the cover off the right cab upright where the cab fuses are. Behind that cover are four relays. Feeding directly into one of those relays was the large diameter wire that came from the 50A cab fuse near the steering wheel. I pulled the relay and replaced it with one of the other three which are all identical. Shazam!!! Everything in the cab now works.

Called local NH dealer and they have another relay that I will pick up tomorrow. The bad relay did work for a few seconds everytime it was energized. That's how the CD player was able to eject the CD but then work. I think the relay is really for the AC compressor and blower. The italians had to get power for the radio from somewhere; so they got it from there. Yeah buddy!!!

All's well that ends well.

 

[jinman]

Very nice! You isolated that problem in spite of the relays having covers that hide the innards. There should be a law that says all relays have to have clear plastiic covers so you can see arcing and sizzling going on inside. You can also be thankful that identical relays are used so you can swap them around. I wonder if the failing circuit might not have more current draw than the contacts are rated for. This could be a recurring problem or it could just be a one tme failure.