Engine/Transmission (1994 - 1998) Back-up Lights

[RossCo]

I have had a problem with my back-up lights for a while. ('97,5sp, 4X4, extended cab)



When I put it in reverse the back-up lights don't come on.



The truck has been in the shop a couple of times. The first time the transmission switch was taken out, cleaned and confirmed that it was working.



The switch was put back in and it didn't turn the lights on. A different switch was put in and the lights came on the first two or three times it was put in reverse but then it stopped working as well. The switch works fine.



Is it the way I shift into reverse?



My trusty shop says that there is no adjustment.



It appears that my options are to by-pass the transmission switch and wire something in the cab or hook up a different set of lights with a switch in the cab.



Has anyone else had this problem?



Thanks



'97, 5 speed, 4X4, Extended Cab, 4" exhaust, AFE Stage 1, Adjusted fuel plate,

Gauges - Boost, Exhaust Temp

 

[JGK]

There is no reason your lights should not work other than a bad or improperly working switch or another problem in the circuit. Hook up another switch you can operate from the cab temporarily. Try to use the plug at the switch if you can for your extension wires to make sure you haven't bypassed more than just the transmission switch. If the problem goes away, it's the switch. If it is still problematic, you have an issue elsewhere in the circuit.



-Jay

 

[Dave M]

I did just what JGK recommened for my 97. I spliced into the wires going to the reverse lights at the connector and ran them to a switch on the dash below the ash tray. I'll take a pic. Got a lighted red switch SPST at Kragen until I got the transmission switch replaced. Now I have both connected but it would blow a fuse when either switch turned on. I found out that because of how the light was wired in the switch it tried to ground out the circuit thru the light. I put in a diode (IN5404 from Radio Shack) and it stopped the problem.



Now I'm adding a relay to the output of the switches to take the load of the transmission switch and running 12 gage wire from the battery feed thru the relay and back to the bu lights. I also added 2 extra lights to the bumper (from NAPA) that are drawing current now thru the transmission switch till I get the relay circuit completed. If you are want to see details and pics let me know.



The stock BU light sucks when backing up a trailer but these NAPA lights are great. They come with a beefy 16 gage right angle bracket that I mounted to the underside of the bumper. The lights slip into a rubber holder like on trailers so the don't mount to the bracket but slip into the rubber grommet into the bracket. If you search on Back up lights you will find lots of reading.



Dave

 

[JGK]

Dave,



I'm not quite just sure why, from a first read of your description, you kept popping a fuse every time you flipped your backup light switch. But it has to be pretty straight forward for RossCo to simply run a couple of wires from the connector at the transmission switch to a temporay switch in the cab to help isolate the problem. The temporary switch itself shouldn't cause any fuses to pop.



My aux. backup lights were wired a bit differently. I also used a relay. I ran a feed directly from the battery to the back bumper and used that as a power source for the aux. lights. But I ran that through the relay with the coil energized by a tap off one of the regular back up light wires. I just pulled a rear tail light assembly and spliced off the hot side wire to the bulb. So when the regular backup lights come on so do the aux. lights.



I also replace my stock back up light bulbs with aftermarket brighter ones. All this is a vast improvement over stock lights.



My only problem is for some reason I'm only getting about 9 volts to the back up lights. I haven't figured that one out yet. I suspect its at a big connector block in the wiring harness I haven't been able to locate.



-Jay

 

[Dave M]

Dave,



I'm not quite just sure why, from a first read of your description, you kept popping a fuse every time you flipped your backup light switch.

I also replace my stock back up light bulbs with aftermarket brighter ones. All this is a vast improvement over stock lights... ... ... ... ...

-Jay

The reason my lighted switch popped the fuse is because in the "Off" position the lighted switch is connected to ground lead on the switch..... so when it is switched off (since when the switch is "Off" it connects the switch output to GND) it shorts out the 12v (if the transmission switch is also closed (Switch "On"... when transmission is in reverse to try to connect the 12v to B/U lights). A diode at the outputs of the switchs prevents the 12v going thru the diode to the switch ground of the lighted switch. Note: Edit 9/11/08 I believe it doesn't matter what position the transmission switch is in, anytime the Lighted switch is in the "Off" position it connects the switch output to GND and blows the 12V fuse supplied to the switch..... in my case I connected the 12v input power to transmission switch to my lighted switch as the switch power source so it blew the transmission switch b/u light fuse.



I put a 1N5404 diode in the circuit and everything is fine. This thread explains it better:



https://www.turbodieselregister.com...sion-discussions/71001-lighting-wiring-2.html



Here are some copies of the schematic and switch from that thread. The first pic of the switch shown below doesn't show the "Off" short position that exits on my lighted swith. If that were like my switch in the "Off" position it would be connected to the GND.



My switch is like in the schematic below not the 1st switch pic shown. The schematic shows 2 lighted switches connected to the GND terminal each of the switch GND leads (and the light is also connected to the gnd lead of the switch) when in the lighted switch "Off" position. This is why my fuses would blow (when the transmission switch was also "On" trying to switch 12V to the B/U lights)! The diodes are in this circuit in the schematic to prevent the short to gnd thru the lighted switches when "Off".



In my case I used one switch on the dash (to manually turn on the B/U lights) and the other would be my transmission B/U switch. When the transmission BU switch is in closed/On position (transmission in reverse) and the lighted dash switch is in the "Off" position the lighted dash switch is grounded but the transmission switch is suppling 12v from the output of the transmission switch. Since both swiyches outputs are tied together, one switch (the lighted dash switch) is suppling gnd thru the "Off" dash switch and the other switch (transmission reverse switch) is suppling 12v so the fuse blows.



Of course the schematic shows two lighted switches but I am useing only one (on the dash). The other switch is the OEM transmission Reverse switch which is not lighted of course.



I used a IN5404 diode at the output of each switch just like in the schematic. Currently my switch output goes to the BU lights and not the relay... . I haven't finished wiring in the relay like in the schematic. If a lighted switch was not used I don't think the diode is necessary but it prevents any possible backfeed problems.



I had trouble understanding why I kept popping a fuse until I read that thread. I didn't realize the lighted SPST switch I got was GND in the "Off" position. The switch has 3 leads: (1). . a GND lead, (2)... a 12v Lead and (3)... an output lead and is wired like the schematic shows.



Dave

 

[Dave M]

Some pics of backup switch, transmission switch and NAPA BU lights.

 

[Dave M]

More pics.

 

[Dave M]

Night shot:

 

[Missouri Mule]

Try this thread.



Back up light switch

https://www.turbodieselregister.com...smission-1994-1998/184162-back-up-lights.html

 

[RossCo]

Thanks everyone for the replies, especially the pictures. I am going to try to wire a switch in the cab. The lights work when triggered manually and the transmission switch works in another truck. The problem seems to be with the fork on the shifter not pushing the switch hard enough to trigger the lights. Since there is no adjustment I guess the only way around it is to do it from the cab.

Thanks again

RossCo

 

[RossCo]

Dave M



My next questions are if I disconnect the connector from the transmission switch do I need the diode? (Since the problem is not the switch or the lights I am just going to by-pass the whole problem and force it. )

I guess you ran the wires up from the boot but I could not get the panel where you mounted the switch off.

Did you run the wires from the transmission connector to the 12v and switched output and ground it separately?



BTW nice lights - once I get this done I will look for similar ones.



Thanks

 

[Dave M]

Dave M



My next questions are if I disconnect the connector from the transmission switch do I need the diode? (Since the problem is not the switch or the lights I am just going to by-pass the whole problem and force it. )

I guess you ran the wires up from the boot but I could not get the panel where you mounted the switch off.

Did you run the wires from the transmission connector to the 12v and switched output and ground it separately?



BTW nice lights - once I get this done I will look for similar ones.



Thanks

First... you only need the diode if you use lighted switches and one or both are lighted like the lighted dash switch I used. If the dash switch is not lighted then forget it. I'm assuming all lighted switches are wired this way but I could be wrong... . mine certaintely was. If the dash switch is lighted then since they are shorted in the Off position you will need the diode. You can use a regular SPST switch and run a seperate light and avoid the lighted switch problem.



Right now I use a relay for mine so when either switch is activated it triggers a relay that has a seperate 12 gage 12v wire from the battery thru the relay (run all the way to the backup lights) to the backup lights in the back. In other words I abandoned the OEM wires going to the backup lights from the transmission switch and ran my own 12 gage higher current wire. You don't have to use a relay or abandon the OEM wiring to backup lights. In fact I used a regular switch for awhile and the OEM wiring. Read on.



I did not run the wire from the transmission connector to the boot but ran it to the drivers fender where I mounted my relay. Prior to my relay I ran 2 wires from the transmission connector (unplugged because my transmission switch was broke... . I replaced it later) up to firewall and into the cab near the steering column and under the dash to my switch.



One of the transmission connector pins is 12V when key is on. Turn key on and verify that you have 12v there. I used that to power the switch. The other wire on the transmission connector goes to the backup lights. Run that wire to the dash switch output so when the switch is on it sends the 12v to the backup lights. You need a diode to prevent blowing the 12v fuse when the lighted switch is OFF or don't use a lighted switch as I said earlier. This whole problem of blowing a fuse is because of the weird way the lighted switch is wired.



If any questions then ask and I'll reply. BTW I got those lights at NAPA for just under $50 total for two with 2 brackets 2 lights 2 rubber inserts and 2 pigtail wires that plug into each light. If you want PN's I'll get them from my NAPA guy. I bought these a few years ago but they are still available and are very nice quality. BTW my night shot shows how bright the lights are with the seperate 12 gage wiring I used.

Dave