Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Just bought a 2003 f250 diesel truck and having an issue with the door ajar light staying on while driving and also the dome light not going out when the key is removed. After a 10 minute delay the dome light does go out but I believe that is a time out feature. Checked the switches and wire to GEM module and they seem to be working properly. When the last door is closed the marker light will flash, indicating the doors are closed. When scanned the P1876 code and a few others came up. Cleared the codes and only the P1876 code returns. What direction should I go from here?
This fine friend is a part time worker at the shop I'm at while he is at our local tech school and I'm trying to help him out with this.
Not sure about the functions of some of these modules and there seems to be some discrepancies with what parts may be on his truck. From what I remember reading in SI after looking at a diagram was that if the vehicle has keyless entry, it has a security module that the door switches run to, and if not, they go straight to the cluster. He does not think it has keyless entry but may have the VSM. I could not communicate with that module with my Launch today though. He also mentioned that the cluster doesn't seem to match up with some info in the owners manual, but that could be a whole separate issue.
I recommended he join our fantastic community to get some direction here from some people who have more experience with these systems. Only working together one day a week doesn't leave much time to help, if we ever even have the time!
I'm not sure what the GEM controls either, or what it really is.
I use the dimmer switch and the light will stay on when keys are removed even when set to the lowest dimmer position. Also doors will not auto lock when driving over 5 mph and vehicle won't go into programming mode for key fob or auto lock.
Ah, that's what I wanted to do on Saturday but forgot. Is that something that would go through the GEM? I know I couldn't communicate with the VSM. Doing some remote diag with OP a few weeks ago I believe we confirmed a change in input voltage with the switches. We also saw that a faint light on the side mirror flashes when the last door is closed, regardless of which door it is, telling us that something knows the doors are open or closed. Not sure what module that is though. Dang it, I wanted to watch those switch pids and we got distracted with all of the dtcs instead.
GEM is where I'd look for PIDs first. And OP if you don't have a way to scan the vehicle yourself take a look at Forscan. Adapters run in the $20 to $100 range and the Windows software is free. Some discussion on it in the link below.
I had checked the continuity of wires from switch to the GEM/VSM and the were good. Also, used a power probe which showed the switches were operating properly. I will download Forscan and pickup an adapter so I can check the PIDs. Thanks for the information.
Finally got a chance to check out door ajar PIDs with Forscan. Could not see them through the VSM but they were accessible through the instrument cluster. The IC showed the front driver switch and passenger switches open and the left rear and tailgate switches closed. Funny thing though when you opened and closed the tailgate and left rear door status stayed closed. Also the diagram of the circuit shows that door switches go directly to the VSM and VSM wired to IC. When I checked the hardware configuration in Forscan it revealed a VSM with a different part number than the one installed. I believe maybe the prior owner may have changed it and not programmed it with previous VSMs as built flash. I'm trying to get the as built data from a Ford dealer in order to flash the module to see if that corrects the door ajar and dome light issues. Can anyone advise me of any other things to check?
You can get as built data from this link. First time you click it it'll take you to a page where you have to select country. After you've done that you can either click the link again or go Free Resources>Quick Guides then scroll down to Module Build Data.
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