scottyc

Got a 1995 audi 90, back up lights don't work. checked fuses and bulbs.
all are in good shape. anything else i can look at

scot

Peter Bell

In message <TcNCc.114128$0y.69178@attbi_s03>
scottyc <scottyc@scotnjen.net> wrote:

> Got a 1995 audi 90, back up lights don't work. checked fuses and
> bulbs. all are in good shape. anything else i can look at

Yes. You need to get hold of a multimeter and check out what voltages
are available at the bulb holders with the ignition turned on and
reverse gear engaged.

I'm not familiar with your particular model, but I would expect that the
outer contact of the bulb holders should be connected to chassis (check
with meter set to measure resistance [should read 0 ohms]). The centre
contacts should be fed with +12V, from a switch mounted on the
gearbox/gear linkage.

If the resistance between holder and chassis is greater than a couple of
ohms, you need to sort that out. If 12V isn't present on the centre
contact, then you'll need to locate the switch on the gearbox and ensure
that it is correctly located, that there is a 12V feed to it, and that
the the 12V reaches the other switch contact when reverse gear is
selected.

The results of these tests should narrow down the areas for further
investigation.

Just a thought - I know that some Audis have the reversing lights
mounted on the boot lid, and a common point of failure is the wiring
between the main body and the boot lid.

--
Peter Bell (Note Spamtrap - To reply, replace 'invalid' with 'bellfamily')

Peter Bell

In message <TcNCc.114128$0y.69178@attbi_s03>
scottyc <scottyc@scotnjen.net> wrote:

> Got a 1995 audi 90, back up lights don't work. checked fuses and
> bulbs. all are in good shape. anything else i can look at

Yes. You need to get hold of a multimeter and check out what voltages
are available at the bulb holders with the ignition turned on and
reverse gear engaged.

I'm not familiar with your particular model, but I would expect that the
outer contact of the bulb holders should be connected to chassis (check
with meter set to measure resistance [should read 0 ohms]). The centre
contacts should be fed with +12V, from a switch mounted on the
gearbox/gear linkage.

If the resistance between holder and chassis is greater than a couple of
ohms, you need to sort that out. If 12V isn't present on the centre
contact, then you'll need to locate the switch on the gearbox and ensure
that it is correctly located, that there is a 12V feed to it, and that
the the 12V reaches the other switch contact when reverse gear is
selected.

The results of these tests should narrow down the areas for further
investigation.

Just a thought - I know that some Audis have the reversing lights
mounted on the boot lid, and a common point of failure is the wiring
between the main body and the boot lid.

--
Peter Bell (Note Spamtrap - To reply, replace 'invalid' with 'bellfamily')

Steve Sears

Scotty C,
What Peter said, but also:
it could be that the switch has broken - check it (most probably mounted on
the transmission, not sure with the 90) to make sure it's operating.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)

"Peter Bell" <peter@invalid.org.uk> wrote in message
news:c4c781c44c.peter@iyonix.earley.fourcom.com...
> In message <TcNCc.114128$0y.69178@attbi_s03>
> scottyc <scottyc@scotnjen.net> wrote:
>
> > Got a 1995 audi 90, back up lights don't work. checked fuses and
> > bulbs. all are in good shape. anything else i can look at
>
> Yes. You need to get hold of a multimeter and check out what voltages
> are available at the bulb holders with the ignition turned on and
> reverse gear engaged.
>
> I'm not familiar with your particular model, but I would expect that the
> outer contact of the bulb holders should be connected to chassis (check
> with meter set to measure resistance [should read 0 ohms]). The centre
> contacts should be fed with +12V, from a switch mounted on the
> gearbox/gear linkage.
>
> If the resistance between holder and chassis is greater than a couple of
> ohms, you need to sort that out. If 12V isn't present on the centre
> contact, then you'll need to locate the switch on the gearbox and ensure
> that it is correctly located, that there is a 12V feed to it, and that
> the the 12V reaches the other switch contact when reverse gear is
> selected.
>
> The results of these tests should narrow down the areas for further
> investigation.
>
> Just a thought - I know that some Audis have the reversing lights
> mounted on the boot lid, and a common point of failure is the wiring
> between the main body and the boot lid.
>
> --
> Peter Bell (Note Spamtrap - To reply, replace 'invalid' with
'bellfamily')

Steve Sears

Scotty C,
What Peter said, but also:
it could be that the switch has broken - check it (most probably mounted on
the transmission, not sure with the 90) to make sure it's operating.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)

"Peter Bell" <peter@invalid.org.uk> wrote in message
news:c4c781c44c.peter@iyonix.earley.fourcom.com...
> In message <TcNCc.114128$0y.69178@attbi_s03>
> scottyc <scottyc@scotnjen.net> wrote:
>
> > Got a 1995 audi 90, back up lights don't work. checked fuses and
> > bulbs. all are in good shape. anything else i can look at
>
> Yes. You need to get hold of a multimeter and check out what voltages
> are available at the bulb holders with the ignition turned on and
> reverse gear engaged.
>
> I'm not familiar with your particular model, but I would expect that the
> outer contact of the bulb holders should be connected to chassis (check
> with meter set to measure resistance [should read 0 ohms]). The centre
> contacts should be fed with +12V, from a switch mounted on the
> gearbox/gear linkage.
>
> If the resistance between holder and chassis is greater than a couple of
> ohms, you need to sort that out. If 12V isn't present on the centre
> contact, then you'll need to locate the switch on the gearbox and ensure
> that it is correctly located, that there is a 12V feed to it, and that
> the the 12V reaches the other switch contact when reverse gear is
> selected.
>
> The results of these tests should narrow down the areas for further
> investigation.
>
> Just a thought - I know that some Audis have the reversing lights
> mounted on the boot lid, and a common point of failure is the wiring
> between the main body and the boot lid.
>
> --
> Peter Bell (Note Spamtrap - To reply, replace 'invalid' with
'bellfamily')