Still tinkering with my electronic Navigator in an 89 LeBaron convertible premium. Ended up cycling through a few units for different reasons - got one that worked (replaced buttons) only to have the VFD apparently die, for instance.
Before I put another one in, I am doing some testing to make sure there isn't an electrical problem that's the real culprit. I put my meter on the connector for the navigator and tested each pin for voltage where appropriate (battery voltage, voltage on ignition, etc.) But I noticed that when I put the meter on port 6, the "fuel flow" or "Fuel Monitor Output" signal, it shows voltage, around 5-6v, even when the vehicle is off. This particular run goes straight back to the SMEC, so I wasn't sure if that was expected behavior or not. I looked through my service manuals and can't find a diagnostic indicating one way or the other. Does anyone know and can shed some light on that?
Is there someone out there who has a 12-button Navigator that can test their wiring harness connector for voltage on pin 6? That seems to be the fastest way for me to track this down. Pin 6 is the furthest left in the top row. Even when the vehicle is turned off I am receiving about 5-6v to it. I am not sure if this is expected or not but I have had a few Navigators work when plugging them in initially only to come back a day or two later and they suddenly don't work. My suspicion is an electrical problem.
Hi there buddy! I’d love to see your LeBaron.....got an album on the site?
I have the ‘85 12-button Navigator in both our Laser XT and my LeBaron GTS. This weekend I can make time to check out the number 6 pin voltage for you. Do you have the wiring diagrams from the Chrysler FSM’s? I can see if there is any explanation from the diagrams for why you’d have 6 volts on it without the car even on....sounds fishy. The only problems I’ve ever had with these Navigators are the dry rotted push buttons that I’ve needed to replace with the new Mauser ones.
Hey just thought of something else....are you sure you have the ground wire from your dash attached to the terminal tab on the back of the Navigator? Without it, there are all sorts of weird things that can happen
I do have the service manual wiring diagram - will snapshot the diagrams and upload them later when I'm back home. I'm not a pro at reading them but I don't see any indication that there should be voltage on that pin when the unit is turned off. I used my meter to test the pinouts under different conditions - I get 5V when the whole car is off and then varying voltage (usually between 3-5V) when the car is running, which that part I would expect as the computer sends voltage signals for fuel consumption.
The behavior I'm seeing is I get a navigator and plug it in to test it - it works great. I replace the buttons and put it back in - works great. Within a few days though the unit stops functioning. At first I thought it was just bad electronics but after it did it more than once the same way I'm convinced something is killing them so I tested the pinouts on the connector. The problem happens when the unit is sitting unused so all that should be going to it is the 12V battery voltage, I believe. So my hunch is that this stray 5-6V constantly being fed into the unit eventually fries the electronics.
For me the unit doesn't function unless I plug in the large ground connector, so that's always plugged in when I'm testing.
Thanks for the reply....no need to upload the diagrams - I have the 85 versions of them. I was just wondering if you had a set yourself or if you were going off on schematics found on line which aren’t always reliable.
Your logic seems reasonable so far, so I think you are chasing down the right path...and I certainly will help however I can. We’ll stay in touch!
I got a chance to do another test - I pulled the 60-way connector on the SMEC and pulled out the fuel flow wire then fed a test wire into its socket. When I put the meter on that wire it still came up 5V, so I know that voltage is coming directly off the SMEC, it isn't phantom voltage inside the wiring harness from somewhere else. Also tested the in-dash connector for the Navigator again with the 60 way disconnected to verify there wasn't other voltage on the line - none found. So I think now the only thing left is to validate if the SMEC does put 5V on that line even when everything is "off" or not. I'm concluding the answer is no and I have a bad SMEC, but let me know what you find when you get a chance to test yours.
Thanks!
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