Mystery battery drain
#31
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I'm happy enough to try again.
#32
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Let's say that works, then you know which system to diagnose based upon the relay.
Last edited by SwayBar; 05-17-2023 at 02:52 PM.
#33
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I've made a bit of progress - but I don't want to tempt fate as more testing is needed.
The current theory is that it's the X-Bus relay sticking on after the car is used. If this is true, it's clearly dropping back out when I disconnect the battery (to insert the ammeter) which is why I don't see the problem. I don't own a clamp meter.
Anyway, I'm recharging the battery and have replaced the relay in the hope that it's as simple as that. I'll give the car another run and see what happens.
The current theory is that it's the X-Bus relay sticking on after the car is used. If this is true, it's clearly dropping back out when I disconnect the battery (to insert the ammeter) which is why I don't see the problem. I don't own a clamp meter.
Anyway, I'm recharging the battery and have replaced the relay in the hope that it's as simple as that. I'll give the car another run and see what happens.
#34
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Have you tried checking the system drain without disconnecting fully?
If you use clips to connect your meter to the battery terminal and the post of the battery, you can carefully lift the lug off if the battery post without de energizing the wiring. You want the meter to be in parallel to the connection, and the major current draws offline before you do so, or the circuit protection fuse in the meter will blow.
(edited to correct typos from mobile keyboard.)
If you use clips to connect your meter to the battery terminal and the post of the battery, you can carefully lift the lug off if the battery post without de energizing the wiring. You want the meter to be in parallel to the connection, and the major current draws offline before you do so, or the circuit protection fuse in the meter will blow.
(edited to correct typos from mobile keyboard.)
Last edited by Hey_Allen; 05-17-2023 at 11:25 PM.
#35
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I had that X bus relay stick on my 88 I found it by touching it with my finger after i had recharged the battery, yes it was warm
#36
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I'm just rambling now.... it definitely looks to be the X-Bus relay that is staying on. However, replacing the relay (with a new one) didn't fix it. I also took apart the old one and it all looked fine. As it consistently drops out (and stays out) when the battery is disconnected, it would not point to a "sticky" relay anyway.
So, it would appear to be something else energising the relay. That's as far as I've got. I now need to have a good look at the wiring diagram and a poke around to see if I can establish what's keeping it energised. It feels like progress....
So, it would appear to be something else energising the relay. That's as far as I've got. I now need to have a good look at the wiring diagram and a poke around to see if I can establish what's keeping it energised. It feels like progress....
#37
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Try removing the rear window defrost relay mext
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thepurpleblob (05-18-2023)
#38
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I'm just rambling now.... it definitely looks to be the X-Bus relay that is staying on. However, replacing the relay (with a new one) didn't fix it. I also took apart the old one and it all looked fine. As it consistently drops out (and stays out) when the battery is disconnected, it would not point to a "sticky" relay anyway.
So, it would appear to be something else energising the relay. That's as far as I've got. I now need to have a good look at the wiring diagram and a poke around to see if I can establish what's keeping it energised. It feels like progress....
So, it would appear to be something else energising the relay. That's as far as I've got. I now need to have a good look at the wiring diagram and a poke around to see if I can establish what's keeping it energised. It feels like progress....
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thepurpleblob (05-18-2023)
#39
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Alan
#40
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I would also wind the windows and sunroof to the 1/2 way positions and try again - keeping the meter connected at all times and removing the ground strap to test.
Alan
Alan
#41
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Thanks - I've got a bunch more things to check to confirm if the X Relay is the issue (or part of the issue) and, if so, why it's causing such a huge drain. Hopefully, I'll not be back later saying "it wasn't that"
#42
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And... it's looking like the rear window heater relay/timer. I'm not calling it yet because I've been wrong before but this seems to be *a* proble if not *the* problem. When the ignition is switched on it comes on (regardless of the switch position) and it stays on when the ignition is off. Somebody did mention checking that...
Just for the record... it doesn't stay on with anything less than the proper battery connections. Clearly, there's too much resistance in a test lamp of meter to keep it pulled in... even with some acrobatics keeping them connected while the battery earth is removed.
Realistically, I'll need to give it a few days to be sure.
Just for the record... it doesn't stay on with anything less than the proper battery connections. Clearly, there's too much resistance in a test lamp of meter to keep it pulled in... even with some acrobatics keeping them connected while the battery earth is removed.
Realistically, I'll need to give it a few days to be sure.