GEAR VENDORS TROUBLESHOOING HELP NEEDED

78F150SUPERCAB4X4

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I need some help with troubleshooting a problem I’m having with my GV Overdrive. I’m not sure why Gear Vendors has an email because every time I’ve tried to contact GV over the years, I have NEVER received a response. So after doing an online search for “Gear Vendors Troubleshooting”, this forum popped up (specifically in this 6.9L & IH & 7.3L IDI Diesels section of this forum) with articles about the GV guys have in their diesel trucks. Although I don’t have a diesel, this topic isn’t about diesel vs gas engines, so I’m hoping you guys are willing to help me.

I have a 78 F150 Super Cab 4x4 with a 4 speed manual. I bought a Gear Vendors years ago (2016) and it’s been working fine the entire time, with the exception of an oil leak coming from the speedo cable and the air vent on the top, that I can’t seem to solve.

As of a few weeks ago, all of a sudden the red light on the on/off control panel I have mounted on the dash will not come on (when I turn the switch on to shift it), which means it’s not getting power for some reason. And since it’s not getting power, it won’t shift and illuminate the green light. But when I turn the key on you can see the red light flash on and then go off all within a millisecond. But when I flip the switch on to shift the gear vendors (switch is mounted on the gear shift), the red light will not come on and it’s not shifting. I inspected the ground wire and there’s no problem with the ground. It’s on bare metal and I tested it with a test light. I don’t know what the problem is or where to look next and I need someone to help me troubleshoot this problem. And since Gear Vendors customer service is absolutely no help whatsoever and won't even respond to my email, I'm looking for help from someone on a forum to assist me. Do anyone of you guys have any idea what the problem is or where I should look next? Did the control panel that all the wires plug into go bad? What can I test and how do I test it? Any advice would be extremely helpful. Thanks for your help.
 

franklin2

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Have you put a testlight on the power wire coming into the system? And after your power switch and gear shift switch?
 

78F150SUPERCAB4X4

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No, because I wasn't sure what to do next. I will do what you suggested and post the results. Hopefully I'll be able to do that tomorrow (Sunday) if the weather doesn't prevent my efforts. Thanks for your help.
 

78F150SUPERCAB4X4

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Here's some more info that might be valuable in diagnosing the problem.....So looking at my wiring diagram for the GV, the power source is coming from the fuse box and it also has an inline fuse. When I was inspecting the ground wire, I did notice the light was coming on on the main control box that all the wires plug into and the fuse is working also. When I pulled the fuse, the light on the control box went off. So it seems the control box is getting power. But I will test power at the power switch and gear shift switch.
 

captain720

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What is your resistance in that ground? Test lights will work with like 25 ohmes but you probably need less than 10.
 

78F150SUPERCAB4X4

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I have no idea. I can check this tomorrow. So to check resistance, I put my multimeter on the ohms setting?? I'm not very good with electrical so I will need advice on this.
 

franklin2

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The testlight should be giving you a good reading. If you were using a digital voltmeter, then your readings from it would be suspect.

From what I am reading, you have power, ground, and the switch connections. Other than one of those being bad, it's going to be the control box. I am not sure if they are available and how much they cost. So double/triple check all the simple stuff first. You do not want it to be the box.
 

hce

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Do you have a 4wd lockout connected? If a switch is flipped there will be an indicator on the control box. Flip the dash switch on and off see if there are changes on the control box, do the same for the foot switch and 4wd lockout. If there is no indication on the control box when flipping a switch it is probably bad switch or wire to switch. 4wd lockout latches once it is activated and the ignition must be turned on and off in 2wd to allow overdrive again.
 

captain720

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To check resistance you connect a test lead to negative post on battery and the other voltmeter lead to the frame ground you are checking and read the ohmes.
 

78F150SUPERCAB4X4

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Captain720--thanks for the info. So what ohm/resistance reading am I looking for? The lower the number the better?

HCI--4x4 lockout is connected. Everything is hooked up and connected per the instructions and everything has been working properly for the past 6 years. I haven't done anything to it or messed with anything. It Just all of a sudden it quit working for some reason. I'll flip some switches and see what happens on the control box.

It's raining right now so not sure how soon I'll be able to work on this. If the rain stops later today, I'll get some testing done. I'll keep you guys posted with the results.
 

captain720

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Yes I have 0.2 ohmes between my dash and battery. You need less than 10 or things get weird.
 

78F150SUPERCAB4X4

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Captain720--Thanks for that info. That's what I needed to know. Unfortunately it's been raining all day and I didn't get a chance to work on this.
 

Cubey

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Try calling Gear Vendors. They have people to talk to at the actual company.
 

78F150SUPERCAB4X4

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Cubey--the problem with that is unless they're open on the weekends, they're closed when I get off work and have a chance to call. That's why I emailed them.
 

Cubey

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Cubey--the problem with that is unless they're open on the weekends, they're closed when I get off work and have a chance to call. That's why I emailed them.
Try leaving a message on their machine with your question and ask them to email because you can't take calls during their office hours? Just a thought.
 
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