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No tail lights

Posted: Sun Aug 12, 2018 8:49 pm
by adam913
Removed the roll bar from my PX2 XLT and the tail lights are not working. I know this is because it is now an open circuit as the lights no longer installed. My question is, can I just connect the wires together to complete the circuit? Or will this cause the BCM to have a heart attack? What other option is there?

Re: No tail lights

Posted: Mon Aug 13, 2018 6:19 am
by kfa1950
Rollbar has Stop Light, not Tail light. The Stop light operates from a relay contacts, not directly to the BCM, the BCM only operates the relay.

Re: No tail lights

Posted: Mon Aug 13, 2018 6:39 am
by saeb
You will eventually kill the FETS in the BCM. It is like connecting the positive and negative terminals on your battery, it will never have a happy ending.

Check the fault codes in the BCM rather than make guesses of the problem as this will most likely tell you the exact problem. It may be likely that it has already been short circuit and needs to be cleared in the BCM to operate again. The BCM will shut circuits down if it senses a short circuit eg. connecting wires together or positive to ground. It will retry numerous times to bring them back on line then eventually shut the circuit down. FETS do not have a finite life span so the issue needs to be rectified before clearing the DTC or eventually you will require a new BCM.

1. Check you have nothing connected together
2. Check none of the rollbar wires are damaged and shorted to ground
3. Check you have not unplugged a wrong connector up under the tub, has it been reconnected properly
3. Check BCM for fault codes, Forscan, Auto Elect or Ford. Most cheap generic scan tools will not help you.
4. Listen to what the fault codes are telling you and rectify then clear fault codes

There will be a puddle lamp DTC and this is normal on a rollbar removal, I have added an option in Forscan to turn off DTC for this circuit but it does not affect anything anyway.

Re: No tail lights

Posted: Tue Aug 14, 2018 8:58 pm
by adam913
Checked codes, came up as below. Cleared and ran car, only ones that came back were the puddle light error and glowplugs.
The strange thing is that the tail lights were on after I got out of the car when I got home today (lights on auto, hadn't locked car yet) so turn switch to on and nothing, put it on auto and nothing, did it with the engine on and off and switch in all different positions and nothing… got me stumped...

Re: No tail lights

Posted: Wed Aug 15, 2018 7:31 am
by saeb
First and foremost, book your vehicle into Ford for the TSB on replacing glow plugs. It is a warranty and is no charge. Expect a day to repair.

Are you saying Brake lights or Parker Lights?

Re: No tail lights

Posted: Wed Aug 15, 2018 6:41 pm
by adam913
Park tail lights, today I had a left and no right. Might just replace the globes anyway, and check the earths.
Is going in for bull bar and canopy tomorrow, I’ll get them to check it too

Re: No tail lights

Posted: Wed Aug 15, 2018 7:07 pm
by RossPat
adam913 wrote: Wed Aug 15, 2018 6:41 pm Park tail lights, today I had a left and no right. Might just replace the globes anyway, and check the earths.
Is going in for bull bar and canopy tomorrow, I’ll get them to check it too
You should have pressed a bit harder when you got a quote.

When I got a canopy quote the said I have to ad $50 for bar removal.

I said if I have to pay extra I will go elsewhere, they removed the bar for nothing.

It takes them 15mins.

Re: No tail lights

Posted: Sat Aug 18, 2018 6:15 pm
by adam913
So replace both brake/tail light globes, now both tail lights working. Neither filaments on each of the globes is blown, both worked when hooked up to a battery... All I can think is maybe the resistance was too high across the globe, I would have thought the bcm would have noted this as an error, or at least noted a problem with the circuit?