C5 WIring problem
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Joined: Jul 2019
Posts: 55
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From: Victoria,BC,Canada
C5 WIring problem
Hello all, I'm a recent owner of a 2002 C5 vert.with 140k km (75K miles).The first week and a half was great everything worked perfect.
However, last Friday went to go out and the FOB wouldn't unlock it no lights came on. There was no power at all. The next day I checked the date on the battery and it was 8 years old. So I bought a new battery and everything was fine again,until the next morning,today. The same problem with the new battery. I can hear what sound to be a relay or such clicking in the engine bay but I can't tell where. So far I've isolated the fault to the fuse box in the engine bay. I have removed every fuse and relay and the problem is still there. It has about a 5 amp draw on it with no key in the ignition. I'm too the point of going under the fuse panel to inspect the connections there.I've partially removed the fuse panel but the wires underneath are holding it down,
I'm using my ammeter and a portable battery to test with. The positive lead is connected to the fuses panel and one end of the ammeter is going to the disconnected negative lead.WHen I touch the negative lead of the ammeter to the negative battery terminal I can hear a muted click and the meter reads about 5 amos.
Has anyone done this? Or is there a special C5 trouble that many have encountered. I suspect i'll find a corroded contact underneath.
Thanks
However, last Friday went to go out and the FOB wouldn't unlock it no lights came on. There was no power at all. The next day I checked the date on the battery and it was 8 years old. So I bought a new battery and everything was fine again,until the next morning,today. The same problem with the new battery. I can hear what sound to be a relay or such clicking in the engine bay but I can't tell where. So far I've isolated the fault to the fuse box in the engine bay. I have removed every fuse and relay and the problem is still there. It has about a 5 amp draw on it with no key in the ignition. I'm too the point of going under the fuse panel to inspect the connections there.I've partially removed the fuse panel but the wires underneath are holding it down,
I'm using my ammeter and a portable battery to test with. The positive lead is connected to the fuses panel and one end of the ammeter is going to the disconnected negative lead.WHen I touch the negative lead of the ammeter to the negative battery terminal I can hear a muted click and the meter reads about 5 amos.
Has anyone done this? Or is there a special C5 trouble that many have encountered. I suspect i'll find a corroded contact underneath.
Thanks
Thread Starter
Advanced
Joined: Jul 2019
Posts: 55
Likes: 11
From: Victoria,BC,Canada
I managed to take apart the engine bay fuse panel looking for any burn marks or corrosion but none were found.It all looks good. Nothing has changed there's still a 5 amp draw with no key in ignition.
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
5A is a lot. Normal draw after all systems go to sleep mode is around 25mA.
There are some "Usual Suspects" for this kind of problem. Take a look at this thread for details on how to proceed, especially Posts 3, 4, 11 and 13.
Post 16 has a faster method to check drains through fuses (relays have to be checked using the "traditional method"). It is so much faster because you only have to wait for the systems to go into sleep mode once.
There are some "Usual Suspects" for this kind of problem. Take a look at this thread for details on how to proceed, especially Posts 3, 4, 11 and 13.
Post 16 has a faster method to check drains through fuses (relays have to be checked using the "traditional method"). It is so much faster because you only have to wait for the systems to go into sleep mode once.
Last edited by GCG; Aug 4, 2019 at 11:26 PM.
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There is a B+ terminal on the under hood fuse box and one on the passengers fuse box. That feed comes from the battery. IF, you remove that lead, that fuse box is dead.
NOTE! When you first hook up the battery or any load, the car wakes up and turns on the approach lights, tries to SHUT the head light buckets, BCM monitors all modules. SO YES, you will see a 5-8 AMP spike. With in 12 Min, If nothing is disturbed electrically, the BCM should start shedding loads and go into SLEEP MODE. That is when you "SHOULD" see the 20-25 milliamp sleep mode current draw.
IF you have a larger than 25 milliamp draw, there are loads that have been known to fail to shut down of continue to draw current.
One is the alternator. Put an AMP METER in series with the BATT Terminal on the back of the alternator. Engine off, you should see ZERO amps. If you see current draw, the diodes inside the alternator are going bad.
Some of the other ones are:
SEAT Control Module
Seat multifunction switch
BOSE Amp
Rear Window Defrost
Take a sleep mode current draw test. AMP meter between battery and NEG Terminal. After 12 min, what is the current draw?????
Bill
NOTE! When you first hook up the battery or any load, the car wakes up and turns on the approach lights, tries to SHUT the head light buckets, BCM monitors all modules. SO YES, you will see a 5-8 AMP spike. With in 12 Min, If nothing is disturbed electrically, the BCM should start shedding loads and go into SLEEP MODE. That is when you "SHOULD" see the 20-25 milliamp sleep mode current draw.
IF you have a larger than 25 milliamp draw, there are loads that have been known to fail to shut down of continue to draw current.
One is the alternator. Put an AMP METER in series with the BATT Terminal on the back of the alternator. Engine off, you should see ZERO amps. If you see current draw, the diodes inside the alternator are going bad.
Some of the other ones are:
SEAT Control Module
Seat multifunction switch
BOSE Amp
Rear Window Defrost
Take a sleep mode current draw test. AMP meter between battery and NEG Terminal. After 12 min, what is the current draw?????
Bill
