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...so my outside ambient temperature is not reading correctly. A little background on the Excursion, a couple years ago I replaced the fuel tank sending unit for the Hutch mod. About a year later the fuel gauge started reading full...it goes to empty when the ignition is off. I haven't done anything with it given the overhead display went from dim reading really bad low temps to no display. So I sent the display off to get it repaired and when I installed it today the compass is working and the miles to empty seems to be working, but I can tell it's not correct. I can hook up Forscan up and read the fuel %...can't do that on the F350, so thinking it's a more complicated PCM. However, the temperature reading is about 30* off...reading 60* when it's really about 90* outside. So I emailed the person that did the repair and he said it only reads the PCM. I figured okay it's the sensor, so I bought and replaced it...and it's still reading the same 60* temperature on the overhead...
So I emailed the guy that repaired the overhead, and he stated the display only reads what the truck tells it to and the issue is something on the truck...possibly the PCM. Anybody know the logistics of other issues that might be causing this...
He is blowing you off, although I've thought of saying it a different way.
Having installed an OH console in my old 2001 XLT F250, I'm familiar with the circuits. The temp reading is direct to console, no need for the PCM to do anything. Vehicles with an OH display also alter the path of the fuel level sensor, where the vehicles without the display go direct from the gauge cluster to the fuel sensor with Vref and back, with an OH display the Vref is also in the display so it knows how much fuel is in the tank for Miles to Empty.
Just to add more ammunition, in the first diagram it shows connector C945 is the harness attachment to the "Trip computer Module". Here is the connector location.
TooManyToys, thank you for this information. I think you may be correct about the Vref given I feel like the fuel mileage to empty is off also. How would the Vref be repaired?
There's no diagram for the circuits themselves on the boards, but when resoldering he may have created a high resistant connection or crossed a circuit into another.
Here is a picture of a resolder job on the typical issue of loose resistors. It's overheated during the work and you can see that the resoldering is poorly controlled and several locations are at risk of crossing circuits. If your board is like this and crosses circuits or other issues, it takes skill to repair. A printed circuit that's broken can be jumped with fine wire if the person knows what they are doing. If bridged with solder, again a competent person should be able to pull off the solder. Even if you don't know the circuits, you can observe the damage and repair.
I've been hobby soldering for 50+ years starting with Heathkits and I find reworking the new anti lead solder difficult to work with, even with temp controlled irons.
I pulled the display module back out of the truck...it's going to get fixed one way or another. Here is a closeup picture of the resistors that were repaired.
The soldering looks OK, but what's going on with the white/yellow resistors? Are they resistors or blank spaces. The image that I posted is the later model OH display, so it will have a different layout.
It looks like there may be a whisker cross-connecting, and the guy left some splatter marked in yellow. That should have been cleaned before going out the door.
I questioned that too this morning when I sent him the diagram you posted...and this was his response:
The resistor arent missing anything you can install them either way sometimes we solder them like that doesnt matter those are all new resistors ..the module is just a receiver it displays what its told . I'm not sure what's wrong with your truck but we repaired the display to display .dont know if this will help I doubt it but sometimes when. Compass get out of calibrations you have to drive in circles both direction . But I know what we did is ok we bench test it before it leaves . Or if you want refund send it back I'll remove parts and send it back like it was I'd be happy to do that . I wish I could help more I really do .with everything else working but temp really sounds like sensor did you replace with new from dealer or aftermarket.sorry for long message heres my number feel free to call me during office hours tomorrow 918-???-????
If I remember correctly those resistors that are white were in there when I sent it to him. There was one that was missing above the pair. I'm wondering if he only replaced that resistor and the others are originals.
Yeah, that's not an intelligent response or a poor adaptation of the English language. IMO, that sounds like a lack of understanding about the display. The troubleshooting logic path should not be temperature and fuel level are off, calibrate the compass. They probably powered the display, it lit up with 8's, good to go.
Had that display been repaired before, as all the OH boards I've seen have the resistor value (620 and 680) visible for QC inspection.
The soldering looks OK, but what's going on with the white/yellow resistors? Are they resistors or blank spaces. The image that I posted is the later model OH display, so it will have a different layout.
It looks like there may be a whisker cross-connecting, and the guy left some splatter marked in yellow. That should have been cleaned before going out the door.
What are you pointing out with the orange arrow? I looked at the the areas in yellow and think they are okay...but then again, I am not really familiar with it.
I only screw with these when I really, really have to. As stated, playing with this solder is not fun. At work, I'd repair what I could of the test equipment we had our electronics group build for us rather than send it up north and be delayed with a vehicle down, but they never used the newer lead-free solder either.
The arrow is pointing to what looks like in the image a solder whisker that bridges between one resistor base and a board ring, which may go to another circuit or be a dead spot. If that is a short between two circuits, that maybe your issue. If it is a bridge, you might be able to break it with a pin, small screwdriver or awl.
The yellow circle shows some errand solder from what I can tell. Sloppy work and if they come loose, not the thing you want floating around a circuit board. The top resistor is the only one not overheated, white in its labeled value coloration. A good electronics tech would have had all the resistors inline, values outward so someone could tell if the correct value was in place, and with all the labels facing one way. It's the way they work.
I only screw with these when I really, really have to. As stated, playing with this solder is not fun. At work, I'd repair what I could of the test equipment we had our electronics group build for us rather than send it up north and be delayed with a vehicle down, but they never used the newer lead-free solder either.
The arrow is pointing to what looks like in the image a solder whisker that bridges between one resistor base and a board ring, which may go to another circuit or be a dead spot. If that is a short between two circuits, that maybe your issue. If it is a bridge, you might be able to break it with a pin, small screwdriver or awl.
The yellow circle shows some errand solder from what I can tell. Sloppy work and if they come loose, not the thing you want floating around a circuit board. The top resistor is the only one not overheated, white in its labeled value coloration. A good electronics tech would have had all the resistors inline, values outward so someone could tell if the correct value was in place, and with all the labels facing one way. It's the way they work.
Boom!...I think the problem is he only replaced that one top resistor, and the issues have to do with the other overheated resistors that should have been replaced.
