89 Audi 100 - No Start, Battery OK, What next?

I jumped in the old Audi tonight at the grocery store, and turned the key as
usual. Only heard a faint "pop" that sounded like a circuit breaker, and the
entire electrical system is dead, no warning lights, no starter, no nothing.
Just to be sure, I had the car jumped. As soon as we connected batteries,
the alarm horn began going off, but I tried the starter anyway - nothing.
Lights or emergency flashers do not work at all. Dome light comes on faintly
when you open the door, but soon fades out. When you try to crank it, the
clock goes dim, but recovers when you stop trying to crank. Battery is
relatively new, and shows 11.8 volts at the jumping post. I do not see any
burned fuses or relays in the fuse box.

What am I missing? Is there a master circuit breaker or fusible link
somewhere that I need to check?

Could it be the ignition switch? The car has the original starter and
ignition switch.

Thanks for any suggestions as to where to start troubleshooting this
problem.


--
Stephen Clark
89 Audi 100
Houston, Texas USA

Stephen Clark wrote:
> I jumped in the old Audi tonight at the grocery store, and turned the key as
> usual. Only heard a faint "pop" that sounded like a circuit breaker, and the
> entire electrical system is dead, no warning lights, no starter, no nothing.
> Just to be sure, I had the car jumped. As soon as we connected batteries,
> the alarm horn began going off, but I tried the starter anyway - nothing.
> Lights or emergency flashers do not work at all. Dome light comes on faintly
> when you open the door, but soon fades out. When you try to crank it, the
> clock goes dim, but recovers when you stop trying to crank. Battery is
> relatively new, and shows 11.8 volts at the jumping post. I do not see any
> burned fuses or relays in the fuse box.
>
> What am I missing? Is there a master circuit breaker or fusible link
> somewhere that I need to check?
>
> Could it be the ignition switch? The car has the original starter and
> ignition switch.
>
> Thanks for any suggestions as to where to start troubleshooting this
> problem.
>
>
Checking the ignition switch is a good idea. When you are doing that
remove the electrical part of the switch (about a foot back of the
instrument cluster) and try to turn it with a flat screwdriver. This is
to check if the crappy pot metal tab inside the ignition that fits into
the electrical switch has broken (the all do sooner or later).

Other ideas Remove the positive battery terminal and check if it is
shorted to ground. If it is start following wires to find out where the
short is (not a fun job).

I seem to remember that there is a controller (probably in the relay
panel under the drivers dash) that shuts down all unneeded circuits when
the starter is engaged. This is to provide max power to the starter.

Another thing to check is in the passenger side kick panel. The positive
lead from the battery in the back has a splice in there where the main
power splits for the fuse box and relays and for the starter. This
splice corrodes over time and can cause all sorts of problems. A quick
check to see if this may be the problem is to check voltage on the
jumper location just behind the passenger side headlight. The voltage
there should be within a half a volt of what you get at the battery
terminal.

You might want to search on the AudiWorld T44 forum for other ideas.
http://forums.audiworld.com/v8/

Don't let the V8 worry you. that is the right place for the I5s as well.

Let us know what you find.

TonyJ
Formerly four T44s
Currently '04 A4 TQ6M

Like Tony said

I would charge up and test existing battery since it is too low to crank
over the Audi. Then deactivate the alarm, I assume this is done by
unlocking the driver's door. I am personally not fond of "jumping" the
battery since it can put a shock on your system and may not work if your
battery is too weak and the cables are not heavy enough.

You will need to look for electrical drains that caused the battery to be
weak. Maybe a bad radiator fan controller which kept the fan on after you
stopped the vehicle.

Just trying to get it started first to make sure nothing is wrong there and
then start looking for why the battery drained down.
--
later,
dave
(One out of many daves)

"Tony" > wrote in message
...
>
>
> Stephen Clark wrote:
>> I jumped in the old Audi tonight at the grocery store, and turned the key
>> as usual. Only heard a faint "pop" that sounded like a circuit breaker,
>> and the entire electrical system is dead, no warning lights, no starter,
>> no nothing. Just to be sure, I had the car jumped. As soon as we
>> connected batteries, the alarm horn began going off, but I tried the
>> starter anyway - nothing. Lights or emergency flashers do not work at
>> all. Dome light comes on faintly when you open the door, but soon fades
>> out. When you try to crank it, the clock goes dim, but recovers when you
>> stop trying to crank. Battery is relatively new, and shows 11.8 volts at
>> the jumping post. I do not see any burned fuses or relays in the fuse
>> box.
>>
>> What am I missing? Is there a master circuit breaker or fusible link
>> somewhere that I need to check?
>>
>> Could it be the ignition switch? The car has the original starter and
>> ignition switch.
>>
>> Thanks for any suggestions as to where to start troubleshooting this
>> problem.
>>
>>
> Checking the ignition switch is a good idea. When you are doing that
> remove the electrical part of the switch (about a foot back of the
> instrument cluster) and try to turn it with a flat screwdriver. This is to
> check if the crappy pot metal tab inside the ignition that fits into the
> electrical switch has broken (the all do sooner or later).
>
> Other ideas Remove the positive battery terminal and check if it is
> shorted to ground. If it is start following wires to find out where the
> short is (not a fun job).
>
> I seem to remember that there is a controller (probably in the relay panel
> under the drivers dash) that shuts down all unneeded circuits when the
> starter is engaged. This is to provide max power to the starter.
>
> Another thing to check is in the passenger side kick panel. The positive
> lead from the battery in the back has a splice in there where the main
> power splits for the fuse box and relays and for the starter. This splice
> corrodes over time and can cause all sorts of problems. A quick check to
> see if this may be the problem is to check voltage on the jumper location
> just behind the passenger side headlight. The voltage there should be
> within a half a volt of what you get at the battery terminal.
>
> You might want to search on the AudiWorld T44 forum for other ideas.
> http://forums.audiworld.com/v8/
>
> Don't let the V8 worry you. that is the right place for the I5s as well.
>
> Let us know what you find.
>
> TonyJ
> Formerly four T44s
> Currently '04 A4 TQ6M

Checked the voltage at the jumper post this morning, and it's 12.45 volts.
BUT, I opened the back doors to remove the battery from under the seat, and
checked the voltage at the battery before disconnecting it: 5.5 volts! How
could just opening the door bring the battery down this far? There is also a
faint buzzing relay that fades out shortly after you open the door. The
resistance from the positive battery cable to ground is about 1.8K ohms, so
it is not shorted, Tony. Also the battery voltage is the same at the
battery terminals, and at the jumping post, so I don't think it's the
splice. Can't check the ignition switch until I get a good battery in
place.

Took the battery to the auto parts store where I got it only six months
ago - their load test says battery is discharged. They said the battery is
needing a charge before they can test it again for warranty purposes.

But it is my feeling that there is a sudden, massive load on the battery,
and Steve Sears on the Audiworld forum came up with a theory that a shorted
starter fits all the facts.

Unfortunately, my trusted Audi mechanic will be out of town until Tuesday,
so I can't get the car to him for diagnosis until then.

I am currently trying to get hold of a battery charger that works, since
mine just blew up! If not, I'll take it back to the auto parts store and
have them charge it up, and test it again.

I certainly appreciate your quick and useful replies!

On Thu, 24 May 2007 14:54:35 -0500, "Stephen Clark" > wrote:

>Checked the voltage at the jumper post this morning, and it's 12.45 volts.
>BUT, I opened the back doors to remove the battery from under the seat, and
>checked the voltage at the battery before disconnecting it: 5.5 volts! How
>could just opening the door bring the battery down this far? There is also a
>faint buzzing relay that fades out shortly after you open the door. The
>resistance from the positive battery cable to ground is about 1.8K ohms, so
>it is not shorted, Tony. Also the battery voltage is the same at the
>battery terminals, and at the jumping post, so I don't think it's the
>splice. Can't check the ignition switch until I get a good battery in
>place.
>
>Took the battery to the auto parts store where I got it only six months
>ago - their load test says battery is discharged. They said the battery is
>needing a charge before they can test it again for warranty purposes.
>
>But it is my feeling that there is a sudden, massive load on the battery,
>and Steve Sears on the Audiworld forum came up with a theory that a shorted
>starter fits all the facts.
>
>Unfortunately, my trusted Audi mechanic will be out of town until Tuesday,
>so I can't get the car to him for diagnosis until then.
>
>I am currently trying to get hold of a battery charger that works, since
>mine just blew up! If not, I'll take it back to the auto parts store and
>have them charge it up, and test it again.
>
>I certainly appreciate your quick and useful replies!

Not to possibly burst your bubble, but that starter motor has a big fat relay
in front of it that won't allow power to even get to the starter unless it has
been "picked" by the ignition switch...

/daytripper
'00 s4 6spd

Got a good charge on the battery, reinstalled it. Battery voltage is now
12.63 installed in the car.

Car starts! Charging voltage is 13.88 at the jumper terminal. Let it run for
30 minutes, turned off, restarted ok. Car is up to normal op temp, shut
down, waited about 5 minutes, then radiator fan came on for 30-40 seconds.
Then 5 minutes later, fan comes on again, but only for a split-second, then
turns off. Hmmmm...

I suspect that there is a drain on the battery that is related to the
radiator fan temp sensor or relays. This could account for the battery going
down. I'll have my mechanic check it out next week, as I don't have the
troubleshooting procedures for the fan controls.

So, Dave, you win! ( subject to verification by my mechanic next week! )
Thanks!

And thanks to all for your insights..you guys are great!

--
Stephen Clark
89 Audi 100
Houston, Texas USA

Thanks, tripper, didn't know that. Good information to remember in the
future.

See Update below...

Glad it is back running!
Yeah keep an eye or ear open for that radiator fan coming on with the engine
off.
You can also make sure that no trunk nor interior lights come on and stay
on.
I saw one vehicle with a drain that was in the vanity mirror. The light
would not come on but there was still a drain there.

--
later,
dave
(One out of many daves)

"Stephen Clark" > wrote in message
...
> Got a good charge on the battery, reinstalled it. Battery voltage is now
> 12.63 installed in the car.
>
> Car starts! Charging voltage is 13.88 at the jumper terminal. Let it run
> for 30 minutes, turned off, restarted ok. Car is up to normal op temp,
> shut down, waited about 5 minutes, then radiator fan came on for 30-40
> seconds. Then 5 minutes later, fan comes on again, but only for a
> split-second, then turns off. Hmmmm...
>
> I suspect that there is a drain on the battery that is related to the
> radiator fan temp sensor or relays. This could account for the battery
> going down. I'll have my mechanic check it out next week, as I don't have
> the troubleshooting procedures for the fan controls.
>
> So, Dave, you win! ( subject to verification by my mechanic next week! )
> Thanks!
>
> And thanks to all for your insights..you guys are great!
>
> --
> Stephen Clark
> 89 Audi 100
> Houston, Texas USA
>

Your mechanic probably knows this but ...

The radiator fan is three speed controlled by voltages provided to is
through a BIG resistor pack on the frame just under the radiator. These
can go bad but usually do not.

Fan speeds one a two have separate relays in the main relay box under
the hood just in front of the drivers side windshield. Fan speed three
has a BIG double wide relay in the AUX relay panel under the dash by the
driver's left knee.

Speed one is operated when the AC is turned on and if it is a turbo it
runs during after-run cooling.

Speed two typically turns on and off if you are driving in traffic.

You would only hear speed three when the temperature is very hot. It
comes on when the temperature gage is about ten degrees to the right of
the center mark.

Any of the relays can cause the fan to run and take the battery down.

Two other components of the system to be aware of are a fusible link for
the fan ground just below the brake master cylinder. The other component
is the thermo switch that operates speeds two and three. It is located
just below the lower radiator hose on the back of the radiator.

Say Hello to Steve Sears.

Tony

Stephen Clark wrote:
> Got a good charge on the battery, reinstalled it. Battery voltage is now
> 12.63 installed in the car.
>
> Car starts! Charging voltage is 13.88 at the jumper terminal. Let it run for
> 30 minutes, turned off, restarted ok. Car is up to normal op temp, shut
> down, waited about 5 minutes, then radiator fan came on for 30-40 seconds.
> Then 5 minutes later, fan comes on again, but only for a split-second, then
> turns off. Hmmmm...
>
> I suspect that there is a drain on the battery that is related to the
> radiator fan temp sensor or relays. This could account for the battery going
> down. I'll have my mechanic check it out next week, as I don't have the
> troubleshooting procedures for the fan controls.
>
> So, Dave, you win! ( subject to verification by my mechanic next week! )
> Thanks!
>
> And thanks to all for your insights..you guys are great!
>

Thanks, Tony, I was vaguely aware of how the fan controls work. The only
thing I have noticed that is abnormal, other than the fan coming on very
briefly when the car is off after a hot run, is that fan speed two has not
worked with the a/c off for quite some time. For example, if I am in stop
and go traffic in the winter, and the engine gets hot enough, fan speed
three will come on ( sounds like an aircraft taking off! ) until the
coolant temp drops below it's preset threshold. The engine never overheats,
so this has not been a problem from a practical point of view, so I have not
done anything about it.

However I usually have the a/c on about eight months out of the year,
because it's hot and muggy in Houston even in the spring and fall. Fan speed
one is sufficient to keep the coolant temp normal with the a/c on, and I'm
not sure that fan speed two ever comes on when the a/c is kept on all the
time.

I'm thinking maybe I should check/replace the relay for fan speed two? If
the temp sensor were the culprit, why would fan speed three operate at all?
Am I on the right track?

I'll send Steve Sears your greeting!

Have a great Memorial Day weekend...


--
Stephen Clark
89 Audi 100
Houston, Texas USA