Reverse light switch keeps going

[LogiSprain]

Hi peeps,

As you can see, I'm new here. I hope you're doing well.

I own a 2011 Ford Fiesta 1.4 Ambiente Hatchback, which takes me from point A to point B. Nice nippy car, reliable and light on fuel.

My current issue is that I've replaced my reverse light switch 3 times in the last 6 months, (The switch that goes into the gearbox).

This is so strange and I don't know where to start looking at what could be causing it. A good old friend of mine advised me that my selector in the gearbox might be faulty.

Any advice would really be appreciated. Just want to add that I experience no issues with shifting gears, no gearbox issues at all.

 

[scotman]

You are on the third reverse switch? Are you using a Ford brand replacement part or some other?
Can you check the connector and confirm that you have power to the switch?

 

[LogiSprain]

@scotman Thanks for the response. I replaced the 1st switch with Ford brand and the following 2 with another brand.

 

[LogiSprain]

Yes, I checked that the connector has power. I used an old wire and connected both points. The reverse lights goes on when doing so.

 

[Handy Andy]

This may be more of a transmission problem - where the Reverse gear - being that it uses an idler gear to make that gear turn backwards to the others, is on the same shifter "fork" as your 5th gear. IT may need a little tweak in the cable to make it work correctly - this might mean a trip to the dealership or a transmission shop.

Auto is similar - but the TCM does the work.

When you replaced these other two switches, did they test out of the car ok? Or were they damaged when removed?

IF the tested ok, the issue may be from a shifter fork alignment. Might just need a new (Auto) solenoid/clutch to fix this issue.

If the switches body is damaged, then the transmission needs service.

 

[LogiSprain]

Hi @Handy Andy Thanks for the information.

From what I can tell, there was no physical damage to the switches when I removed them. It looked brand new. However, they did not work outside the car either. I manually pressed the switch "ball", but nothing came from it.

 

[Handy Andy]

Wow...two in a row...

Ok, since they "Failed" and no signs of physical damages.

How's the backup lights doing?

I mean, if you have not had to change ANY light bulbs in a while - you might want to inspect them.

This fail, in the same fashion, reminds me of the times that the wires to the backups went bad on an older car of mine, wound not blow the fuse, but popped the switch contacts- at the switch, in the transmission.

Seems that the switch is rated for a given amount of current, but if the short or bad bulb faults this instead, the power supply can burn out the switch much like a fuse does when overloaded - it simply blows open because the resistance of the contacts, the wire AWG (gauge) and the fuse that supplies this from the fusebox, the switch contact rating went first.

Reminds me of murphy

The most expensive part of a Circuit will protect the 2 cent fuse by blowing first.
​

 

[LogiSprain]

Ah, you know. . . My back window has been fogging up on the inside during the night. I'm wondering now if this could not perhaps be the cause, (or reason) behind the wiring perhaps being faulty. I must add that the fogging-up has only been for the last 2 weeks, to where the replacement of switches has been for 6 months.

I'll open the boot and remove the lights tomorrow morning first thing and inspect them.

The only other piece of information I can give is that when the switch starts going, the reverse light starts going on and off when backing up.

Only sometimes, putting it back into neutral and then reverse keeps it on. However, this is only while the switch is still working.

I'll inspect all the bulbs and wiring.

 

[Handy Andy]

This may be from a wire the "Grounds" to the sheet metal but is supposed to be live (grounds before it gets to the bulb - so it acts like a dead short - bulb stays dark) - possibly in the "Grommet" section of where you pull out the taillight, to expose the bulbs. There is a grommet and on the other side - in the firewall - pulling the felt back, is the harness itself.

I have been finding the reflector used in the housing itself can dig into the bulb and the sockets making them "short out" the contacts at the bulb - which will damage the switch because it uses a lower current rating than the fuse that protects the bulbs from "dead shorts" which does you little good.

Since the harness is larger than the grommet, the individual lugs have to be pried out and removed - snaked thru to remove the wires to these bulbs - and to even change the harness out to swap in a newer taillight that has different "sockets" that your older ones will not fit into

 

[LogiSprain]

Hey Guys,

So - I have some feedback. Got the new switch and fitted it. The reverse lights sometimes go on and sometimes not.

I tested the reverse switch outside and work fine.

What I did pick up is the "click" noise it makes when putting it into reverse. When it makes the click noise, the reverse light does not go on. When it doesn't make the click noise, the reverse lights go on.

I wonder if the length of the switch is too short.