Dash, side markers and right parking lights

[Visions]

Hello,,,89 535i,,, have a bit of a problem,,, the dash gages, climate control lights, license plate and right parking lights front and back went out at the same time... also the side markers are out all the way around and I am not sure if those went out at the same time...

I have checked the LKM by swithcing with my other car and it doesn't help...

Fuses all look fine and I even changed #5 just to be sure and it didn't help...

I have read about the trunk being a problem spot... but I looked for the junction near the left of the side trunk lid and all I saw were wires... is there a junction somewhere near or back farther that causes problems?

I tried new bulbs in parking and side markers but nothing has helped...

Thanks for your help!... It's supposed to be decently warm tomorrow so I would like to get this taken care of before winter really kicks in...

[Javier]

funny thing is that they use different contacts in the Light switch for the interior or park lights, so I can hardly believe the issue is in the switch.

Make a good inspection on the fuse F5, check with a meter is possible, verify fuse socket is OK, and finaly, as a last resource, check for voltage at the Red/Blue wire coming into the Lights Switch.

Javier

[Visions]

Javier,, on rear parking I checked for voltage and didn't have any... the break and turn showed voltage...

Both the old and new fuse was tested to be good...

For the socket I should have voltage across it.... Now what if I don't?

[Javier]

no, there should be no voltage across, but you should have voltage from any of the fuse terminals to ground (car body metal).

If you remove the fuse and light switch is tuned on, yes there should be voltage across. If not, also check voltage to ground from both pins holding the fuse, one of them should be 12Vdc, if not, the problem is that the fuse is not getting power (cut wire?) and you should debug the circuit up stream towards the battery.

If you have voltage at one pin and still no voltage across, then you have an open circuit down stream, probably at the wire going from the fuse to the light switch (Red/Blue one).

Javier

[Visions]

is it possible to have one of the lights short out the circuit and not blow the fuse?

[Javier]

There is no way to have an over current without blowing them. The question is: Is there a short to ground? As it is not the only possible fault. The short-circuit to ground is a fault in which the positive wire feeding a load contacts the negative wire (ground in cars) before reaching that load (in or after the load, it is no longer a positive wire). This short-circuit is equivalent to have a 0 resistance load (thus his name) and as load current is the quotient of voltage over resistance, current pretends to rise to infinitum blowing the fuse. Another fault blowing fuses is Overload, it is caused by having in a circuit so much loads, so the sum of their currents is over the total current the fuse can allow. Fuse operation is based in inverse curves, it means the more the current the shorter time it takes to blow it, some times, over currents are really small and it can takes minutes (or hours) of overload operation to blow the fuse. This faults are specially risky, as if the fuse is not properly rated to protect the wires involved in the circuit, it can overheat the wires causing fires, or insulation damage that will lead to short-circuits and major damages on the surroundings.

A third possible type of fault does not blow fuses at all, it happens when the circuit opens, not carrying power any longer to the load. It is the case when wires are severed, pulled out of the connectors, or simply corroded in the terminals. If the exposed wires after the rupture of the circuit never contacts the ground, there will never be a short nor blown fuses.

These were all single circuit faults, but as you may guess, in a multiple circuit harness, there is also the possibility of having short-circuits (as straight connections) between wires of different circuits, but as not being at different voltages (both at 12 V, at 12 V after a switch operation, or both at ground level) there may not be high currents nor fuse operations. This causes things to work funny, as turn on wipers when lights are turned on, or similar gremlins.

In our e34, there is a typical source of electrical problems as it is the left trunk lid hinge harness. It generally involves several severed wires, some times short-circuited between them, and almost never involving blown fuses, but believe me, there is a lot of issues it crete in reverse and interior lights, and in the central locking system.

Javier

[Visions]

You have been a great help and I definately appreciate your time and knowledge...

One last thing... I didn't see a wiring harness on or near the trunk lid hinge.... only see taped wires.... is it back behind the carpeting?

I am off of work tomorrow and will use the knowledge you gave me to run down this problem...

Thanks alot

Visions

[Paul in NZ]

wires comes from under the parcel shelf and onto lh hinge ussually covered with black plastic sheath on the hinge itself.It is this sheath which causes the problem by bending the wires in a tight radius

[Javier]

You may notice that opposite to the right, left one has a black plastic cover concealing the wire harness connecting body wiring to the lid wiring. There are wires for reverse lights, rear fog lamps, license lamps, interior trunk lights and trunk power lock. You talked about taped wires, so if your car doe not look like the pictures, then guess somebody did repair the hinge harness before.

As you are not blowing fuse F5 and your description said interior signals lights and license and parking lights are out, being them controlled by different contacts in the light switch (making circuits independent after light switch), bet your problem is before light switch.

Javier

[Visions]

Thanks guys,,, I will check out the hinge in the morning,,, no wonder I couldn't find the harness...

Also Javier,,, I pulled F5 and tried to get V to ground but it didn't read a thing... but maybe I didn't have a good ground...