6.9-250 Posted April 22, 2021 Share Posted April 22, 2021 When in reverse the lights flicker, or stay on, or sometimes off. I have to move the shifter just to where it engages reverse for the lights to stay on (which almost takes it out of reverse). I checked my service manual and it says to refer to group 16 (not sure what "group" is). I went to section 16 and it references manual transmission. I checked the evtm and they show exactly where it is on the manual, not auto. They say the location of the switch is either on the trans or neutral safety switch. If its in the neutral safety switch..is it adjustable or the switch requires replacement? Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 22, 2021 Share Posted April 22, 2021 You may have a bad switch or a bad connection to the switch. The switch is on the side of the transmission, and you can find it by following the two wires that go to it - Pk/O and Bk/Pk. If the connector is plugged in well then I think the switch is bad. I had to replace one recently. Link to comment Share on other sites More sharing options...
85lebaront2 Posted April 22, 2021 Share Posted April 22, 2021 It is adjustable, but chances are the switch may be bad, There are 4 wires going to it and on my 1986 the plug was at the transmission crossmember to frame attachment on the driver's side. The switch is a curved plastic assembly and requires removal of the downshift linkage. Don't mind the backwards switch position or strange linkage, I was in the process of switching to a 1996 interior and had to adapt the cable shifter to the existing C6. Hole circled is for setting the switch, the new one will come with a pin in that hole to hold the switch in the neutral position. It is installed and the pin removed after tightening it down. Link to comment Share on other sites More sharing options...
6.9-250 Posted April 24, 2021 Author Share Posted April 24, 2021 It is adjustable, but chances are the switch may be bad, There are 4 wires going to it and on my 1986 the plug was at the transmission crossmember to frame attachment on the driver's side. The switch is a curved plastic assembly and requires removal of the downshift linkage. Don't mind the backwards switch position or strange linkage, I was in the process of switching to a 1996 interior and had to adapt the cable shifter to the existing C6. Hole circled is for setting the switch, the new one will come with a pin in that hole to hold the switch in the neutral position. It is installed and the pin removed after tightening it down. Thanks for the advice. It put me on the right track. The reason I could not find it in the shop manual is because I needed to look under the neutral safety switch. While they don't reference the backup switch being part of the neutral safety switch, they do mention after setting the neutral safety switch to check if the reverse lights come on. The manual transmissions have an actual dedicated switch in the transmission. The setup instructions are in the shop manual. I am not going to bother trying to set the current neutral safety switch as it may be worn out. They are not expensive and if that's the original one on the truck, it has served its time, lol. Link to comment Share on other sites More sharing options...
6.9-250 Posted September 4, 2021 Author Share Posted September 4, 2021 Thanks for the advice. It put me on the right track. The reason I could not find it in the shop manual is because I needed to look under the neutral safety switch. While they don't reference the backup switch being part of the neutral safety switch, they do mention after setting the neutral safety switch to check if the reverse lights come on. The manual transmissions have an actual dedicated switch in the transmission. The setup instructions are in the shop manual. I am not going to bother trying to set the current neutral safety switch as it may be worn out. They are not expensive and if that's the original one on the truck, it has served its time, lol. Installed a new STANDARD MOTOR PRODUCTS NS26 and the reverse lights are working perfectly now. The shop manual refers to setting the switch while installed. This was not going well. I ended up taking it back off and setting it on the bench (inserting a small drill bit and turning it until all the holes line up). Done while in neutral position. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 4, 2021 Share Posted September 4, 2021 Installed a new STANDARD MOTOR PRODUCTS NS26 and the reverse lights are working perfectly now. The shop manual refers to setting the switch while installed. This was not going well. I ended up taking it back off and setting it on the bench (inserting a small drill bit and turning it until all the holes line up). Done while in neutral position. That's an interesting trick! I've not adjusted one of those switches, but hope to remember that if I do. Glad you got it working! Link to comment Share on other sites More sharing options...
85lebaront2 Posted September 4, 2021 Share Posted September 4, 2021 Installed a new STANDARD MOTOR PRODUCTS NS26 and the reverse lights are working perfectly now. The shop manual refers to setting the switch while installed. This was not going well. I ended up taking it back off and setting it on the bench (inserting a small drill bit and turning it until all the holes line up). Done while in neutral position. The drill is exactly the preferred method on these. The Motorcraft one I installed on Darth years ago came with a plastic pin to hold it in the neutral position. The MLP (manual lever position sensor) on the E4OD adjusts in a similar fashion. Link to comment Share on other sites More sharing options...
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