OBDII connector question
Thread Starter
|
Lead Driver
Joined: Nov 2005
Posts: 8,480
Likes: 4,973
OBDII connector question
One of you tech-types, maybe you can tell me about this.
On the under dash OBD port connector, there is an extension cable on it that plugs into the OBD harness to the PCM.
Also on the back of this OBD port is another cable that runs somewhere up in the dash.
Now, the port and extension harness unplugs from the OBD harness to the PCM and that PCM harness has another OBD plug on it, and the tuner my mechanic uses plugs into the harness there, bypassing the under dash port which he disconnects before doing uploads.
I asked him what this extension with the second cable going to it does and he could not tell me.
What I am wondering, is this second cable on the under dash connector how automatic updates from Ford gets uploaded to the pcm?
First pic is the under dash port and the arrow points out the second cable that runs up inside the dash.
Second pic is the OBD plug (white) on the PCM harness that the under dash port connector plugs into.
On the under dash OBD port connector, there is an extension cable on it that plugs into the OBD harness to the PCM.
Also on the back of this OBD port is another cable that runs somewhere up in the dash.
Now, the port and extension harness unplugs from the OBD harness to the PCM and that PCM harness has another OBD plug on it, and the tuner my mechanic uses plugs into the harness there, bypassing the under dash port which he disconnects before doing uploads.
I asked him what this extension with the second cable going to it does and he could not tell me.
What I am wondering, is this second cable on the under dash connector how automatic updates from Ford gets uploaded to the pcm?
First pic is the under dash port and the arrow points out the second cable that runs up inside the dash.
Second pic is the OBD plug (white) on the PCM harness that the under dash port connector plugs into.
Fleet Mechanic
Joined: Aug 2011
Posts: 1,577
Likes: 264
Every time I’ve seen one of those “Y” harness put in and the gateway module is zap strap up to some wiring is for either a fleet monitor (gps/cell) or a tracker of some sort, it could also be for a gauge display/tuner though less likely.
Laughing Gas
Joined: Aug 2021
Posts: 917
Likes: 513
Ford OTA updates go through the WIFI connection IIRC.
Bob
Thread Starter
|
Lead Driver
Joined: Nov 2005
Posts: 8,480
Likes: 4,973
Okay, thanks for the responses.
So I have had this truck since new, this is not something added on, it came from Ford this way.
And, yes, OTA updates come by wifi, but there has to be some connection to the PCM for the wifi sent updates to get downloaded to the pcm, wifi is not built into the pcm.
I will try to follow the cable and see if I can find where it goes.
So I have had this truck since new, this is not something added on, it came from Ford this way.
And, yes, OTA updates come by wifi, but there has to be some connection to the PCM for the wifi sent updates to get downloaded to the pcm, wifi is not built into the pcm.
I will try to follow the cable and see if I can find where it goes.
Cross-Country
Joined: Nov 2024
Posts: 69
Likes: 13
One of you tech-types, maybe you can tell me about this.
On the under dash OBD port connector, there is an extension cable on it that plugs into the OBD harness to the PCM.
Also on the back of this OBD port is another cable that runs somewhere up in the dash.
Now, the port and extension harness unplugs from the OBD harness to the PCM and that PCM harness has another OBD plug on it, and the tuner my mechanic uses plugs into the harness there, bypassing the under dash port which he disconnects before doing uploads.
I asked him what this extension with the second cable going to it does and he could not tell me.
What I am wondering, is this second cable on the under dash connector how automatic updates from Ford gets uploaded to the pcm?
First pic is the under dash port and the arrow points out the second cable that runs up inside the dash.
Second pic is the OBD plug (white) on the PCM harness that the under dash port connector plugs into.
On the under dash OBD port connector, there is an extension cable on it that plugs into the OBD harness to the PCM.
Also on the back of this OBD port is another cable that runs somewhere up in the dash.
Now, the port and extension harness unplugs from the OBD harness to the PCM and that PCM harness has another OBD plug on it, and the tuner my mechanic uses plugs into the harness there, bypassing the under dash port which he disconnects before doing uploads.
I asked him what this extension with the second cable going to it does and he could not tell me.
What I am wondering, is this second cable on the under dash connector how automatic updates from Ford gets uploaded to the pcm?
First pic is the under dash port and the arrow points out the second cable that runs up inside the dash.
Second pic is the OBD plug (white) on the PCM harness that the under dash port connector plugs into.
I am a GPS Installer and I can tell you without a shadow of a doubt, that the "Y" harness is for a Geotab GPS or other tracker. If it was Buy Here Pay Here, it would not be that easy to unplug. Unless the BHPH stealership, wanted it for tracking only and not starter interrupt. If you bought your truck used, that is exactly what is in line. You can unplug it from the OEM OBDII and reinsert the OEM plug back in its bracket or rescure it with the 2 7mm nuts. As the other poster mentioned, it could be for a tuner or pedal commander, but if you bought it new, I would be asking questions. I do know some stealerships in high crime areas or areas of known vehicle thefts, protect their vehicles with GPS and when it is sold, they remove it.
Last edited by PURSUIT ELECTRONICS; Feb 5, 2026 at 09:17 AM.
Thread Starter
|
Lead Driver
Joined: Nov 2005
Posts: 8,480
Likes: 4,973
Okay, guess y'all were onto something, it is some kind of aftermarket tracker after all apparently, the bracket it fits in is a flimsy POS, and broken anyway.
I pulled down the oem OBD harness and the original bracket for the connector is still attached but was tied up with a zip tie, put it back where it goes.
I traced the cable from the aftermarket gizmo as far as I could, and I could pull on it and here something loose stuck down in the inner panel knocking around as I pulled it, but I could not get it to come out.
Only thing I could imagine is some time when it was in a dealer shop for work, they stuck this thing in there for some reason.
Maybe one day I will get industrious and take the inner panel apart and pull it out, but it is disconnected so it isn't working anymore, whatever it is.
I ordered this truck and picked it up right away when it came in, don't think it's been on there since new.
I wish I knew for sure where it came from, I would go to them and raise holy hell.
I pulled down the oem OBD harness and the original bracket for the connector is still attached but was tied up with a zip tie, put it back where it goes.
I traced the cable from the aftermarket gizmo as far as I could, and I could pull on it and here something loose stuck down in the inner panel knocking around as I pulled it, but I could not get it to come out.
Only thing I could imagine is some time when it was in a dealer shop for work, they stuck this thing in there for some reason.
Maybe one day I will get industrious and take the inner panel apart and pull it out, but it is disconnected so it isn't working anymore, whatever it is.
I ordered this truck and picked it up right away when it came in, don't think it's been on there since new.
I wish I knew for sure where it came from, I would go to them and raise holy hell.
Last edited by Ltngdrvr; Feb 5, 2026 at 11:14 AM.
Trending Topics
Cross-Country
Joined: Nov 2024
Posts: 69
Likes: 13
Yessir, chances are, it is as high in the dash as it can get. In Fords, you can usually pull the side panel on the side of the dash and it is sometimes placed there or if small enough, it is in the A Pillar. But, you can just keep the company who installed it, guessing where the truck is. I know when I install the trackers, they go as high in the dash as possible and zip tied in several places, so, be careful when playing tug-o-war with the harness. You could cause unwanted damage to other harnesses. If it doesn't bother you, you can just unplug it from the OEM OBDII and leave it in place. But I would be curious which tracker is in the truck. Let me know and I can assist you in locating who put it in. By the way, IF it was installed as part of Secondary Finance requirements...you could be in default of your contract, should that be the case. Finance companies can repossess the vehicle for defaulting on the contract and if the GPS is part of that (read the fine print), it can be picked up. I am not saying this is the case, but Secondary Finance companies are brutal when it comes to vehicles.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Thread Starter
|
Lead Driver
Joined: Nov 2005
Posts: 8,480
Likes: 4,973
Yessir, chances are, it is as high in the dash as it can get. In Fords, you can usually pull the side panel on the side of the dash and it is sometimes placed there or if small enough, it is in the A Pillar. But, you can just keep the company who installed it, guessing where the truck is. I know when I install the trackers, they go as high in the dash as possible and zip tied in several places, so, be careful when playing tug-o-war with the harness. You could cause unwanted damage to other harnesses. If it doesn't bother you, you can just unplug it from the OEM OBDII and leave it in place. But I would be curious which tracker is in the truck. Let me know and I can assist you in locating who put it in. By the way, IF it was installed as part of Secondary Finance requirements...you could be in default of your contract, should that be the case. Finance companies can repossess the vehicle for defaulting on the contract and if the GPS is part of that (read the fine print), it can be picked up. I am not saying this is the case, but Secondary Finance companies are brutal when it comes to vehicles.
It's been in 3 dealer shops for warranty work, never got any other work that either I didn't do or that I watched everything that was done to it, so had to be one of those 3 dealerships that stuck it in there.
Last edited by Ltngdrvr; Feb 5, 2026 at 11:53 AM.
Thread
Thread Starter
Forum
Replies
Last Post
bette
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
8
Mar 14, 2023 08:24 PM
Caveman Eric
1987 - 1996 F150 & Larger F-Series Trucks
8
Aug 30, 2017 11:22 AM
minnesota-clint
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
10
Feb 17, 2014 12:18 PM
Jeepers2003
1973 - 1979 F-100 & Larger F-Series Trucks
12
Sep 11, 2010 05:59 PM