Technical Tail lamp fuse location.

[Brooky58]

Got a problem with my Panda 1.2 Dynamic Eco 2010. In the process of wiring in towbar electrics, I’ve lost the feed to the nearside tail lamp. The bulb tests fine and the offside tail lamp works. I can only assume that I’ve created a short circuit at some point and blown a fuse. No problem I think, except that my owners manual doesn’t seem to make any reference to fuses for either side or tail lamps. I don’t think it’s just me being a bit blind but I’ve been through the fuse lists several times and cannot find any fuse reference for either side or tail lamps. Can anybody help please?

 

[koalar]

fuse for the rear lights is on the body computer

It does both sides so it's not this

Is the bulb an led, if so it will matter which way round it's plugged in

If you put the brakes and hazards on together are both rear indicators the same brightness


You are fitting the tow bar via a bypass relay, the lights are controlled by the body computer, if it senses too little or too much current it can cut the power to the bulbs

 

[Brooky58]

Thanks for your reply. Fuse F39 is not blown. The bulb is not an LED. If I switch on the hazard lights and then press the brake pedal, the brake lights operate properly and the indicators don’t dim. I have also just noticed that the nearside FRONT sidelamp is also not working. So it seems that one whole side is affected, as far as sidelights are concerned. With the sidelights on, the wire feeding the nearside tail light shows only 30 mV, so practically nothing. The nearside front sidelamp bulb looks a little blackened. Is it possible that failure of this bulb could cause the tail lamp to also malfunction?

 

[koalar]

Thanks for your reply. Fuse F39 is not blown. The bulb is not an LED. If I switch on the hazard lights and then press the brake pedal, the brake lights operate properly and the indicators don’t dim. I have also just noticed that the nearside FRONT sidelamp is also not working. So it seems that one whole side is affected, as far as sidelights are concerned. With the sidelights on, the wire feeding the nearside tail light shows only 30 mV, so practically nothing. The nearside front sidelamp bulb looks a little blackened. Is it possible that failure of this bulb could cause the tail lamp to also malfunction?

If the wrong wattage bulb is used it's not unknown for all of one side to get switched off by the body computer

By that reckoning, a faulty bulb could cut power to both front and back


No point in guessing, you have identical bulb on the otherside of the car, just swap them over and see if the fault follows the bukb

 

[Brooky58]

I’ll try that tomorrow. Many thanks for your help.

 

[Brooky58]

Well, I’ve done the bulb swap side to side and renewed the suspect nearside front sidelamp bulb and the fault is still apparent and is on the same side. I guess that either the fault lies in the body computer or I’ve made a mistake with the wiring. There are a lot of wires in the harness that I’ve tapped into. Wiring for the heated rear screen, rear wiper/washer, electric tailgate release latch. I’ll go through the wiring again from the start, when the nearside tail light was the first wire I tapped into and it worked.

 

[koalar]

You are fitting a tow bar bypass relay,


Yellow and black would be my guess for the side side light, at least that what's on the circuit diagram, but there not always 100%

If you told me the colour of all the wires going to the left light cluster i can match up the various circuit diagrams and post the correct one

 

[Brooky58]

You mention a bypass relay. The only extra device I have, that I’ve not fitted, is what I assumed to be just a sounder for the indicators. If it performs another essential function, I’ll get it fitted right away.
Yes, yellow and black is the nearside tail light.

 

[koalar]

. In the process of wiring in towbar electrics

I am in the dark at this end, as to what you you are using

You mention a bypass relay

One of these is the normal way to wire a tow bar

you fetch a separate heavy duty wires to something like this

Then it just senses which bulbs are turned on and then uses it's own power to activate the lights on the trailer, without some kind of interface and the bulbs are wired in parallel the current increases, you are altering the loads on wires, connectors and body computer

 

[Brooky58]

At the moment, I’m simply cutting the original harness and then re-joining with a third wire from the towing plug 7 pin wiring. I shall be getting one of those by-pass relays by the look of things! Thanks again for your help. As an aside, I didn’t need to do this on my previous ‘96 Toyota Starlet but I guess that didn’t have a ‘body computer’.

 

[koalar]

At the moment, I’m simply cutting the original harness and then re-joining with a third wire from the towing plug 7 pin wiring. I shall be getting one of those by-pass relays by the look of things! Thanks again for your help. As an aside, I didn’t need to do this on my previous ‘96 Toyota Starlet but I guess that didn’t have a ‘body computer’.

Depends on the connectors and wires as well as body computer

Two bulbs in parallel is roughly twice the current

Anyhow let's get back to a working system

Are the number plate lights on

 

[Brooky58]

All the lights work apart from nearside side and tail lamps.

 

[koalar]

Right, good

We have two way of going forwards

One measure loads of things

Or

Two connect a scantool that can interrogate the body computer

Second option would probably save some time and effort,

It would have to be full version of MultiECUscan, Delphi, wow or similar


The free version of alfaobd and an android phone with a cheap £5 Bluetooth elm327 might work, can't say, never tried connecting to the body computer myself and I no longer have a Panda


There may be someone nearby that can plug in for you

 

[Brooky58]

Okay. I’ve ordered a by-pass relay and will be wiring that in. Once I’ve done that and assuming I’ve got it right, will the body computer recognise this and reset itself? If not, will a hard reset (battery disconnect and reconnect) do it, or do I need to get my garage to clear it?

 

[The Panda Nut]

At the moment, I’m simply cutting the original harness and then re-joining with a third wire from the towing plug 7 pin wiring. I shall be getting one of those by-pass relays by the look of things! Thanks again for your help. As an aside, I didn’t need to do this on my previous ‘96 Toyota Starlet but I guess that didn’t have a ‘body computer’.

You will overload the wiring and systems doing it this way. Get a relay. I wpoiuld disconnect immediately. Check the wire has not been broken where you joined into it. Easily done. Relay is easy to install see Panda downloads and there are several documents in the Panda section relating to the wiring for a tow bar that may assist you. Removing teh towing wires may restore your light. The cars wiring is not capable of conducting the current required to power up trailer wires. (Black Magic at work) Some say you cannot wire up a can bus equipped car but using a relay its little differernt to a standard job in terms of difficulty.

 

[koalar]

Okay. I’ve ordered a by-pass relay and will be wiring that in. Once I’ve done that and assuming I’ve got it right, will the body computer recognise this and reset itself? If not, will a hard reset (battery disconnect and reconnect) do it, or do I need to get my garage to clear it?

Some codes reset automatically
Some codes reset after a few restart, engine coolant sensor is 5 restarts

A few are safety related and need clearing via software, the only ones I have noticed that require software are accelerator and airbag

Battery disconnect does nothing to reset any codes, there store in none volatile memory


It will start the ecu and body computer afresh and loose the real time clock, only need disconnect and reconnect for this

 

[Brooky58]

That’s clear. Many thanks again.

 

[koalar]

I trying to avoid going directly to the body computer, messing up here by shorting two pins while measuring voltages could be a very expensive mistake, plus access isn't great, could even wright the car off, I trying to avoid making a bad situation worse

The front and rear side light lights use completely different wires and grounds except pin 15 and 11 are possible joined internally inside body computer

If you connect to the body computer via software it will just tell you open circuit or short to ground and so on

From this end it's hard to know how best to start, depends on your ability, tools, experience

If you disconnect the rear light clusters completely does the front light come back on

 

[Brooky58]

You will overload the wiring and systems doing it this way. Get a relay. I wpoiuld disconnect immediately. Check the wire has not been broken where you joined into it. Easily done. Relay is easy to install see Panda downloads and there are several documents in the Panda section relating to the wiring for a tow bar that may assist you. Removing teh towing wires may restore your light. The cars wiring is not capable of conducting the current required to power up trailer wires. (Black Magic at work) Some say you cannot wire up a can bus equipped car but using a relay its little differernt to a standard job in terms of difficulty.

Many thanks. I haven’t even plugged a trailer in yet but I’ll disconnect the towing electrics wires tomorrow when the weather’s better and see what effect that has.

 

[Brooky58]

I trying to avoid going directly to the body computer, messing up here by shorting two pins while measuring voltages could be a very expensive mistake, plus access isn't great, could even wright the car off, I trying to avoid making a bad situation worse

The front and rear side light lights use completely different wires and grounds except pin 15 and 11 are possible joined internally inside body computer

If you connect to the body computer via software it will just tell you open circuit or short to ground and so on

From this end it's hard to know how best to start, depends on your ability, tools, experience

If you disconnect the rear light clusters completely does the front light come back on

Thanks. I’ll start by disconnecting the towbar wiring completely and see what effect that has. That will just leave all the original wires re-joined via connectors.