Dash Common Power
Discussion
Another problem, another post :-)
Took the dash top off earlier to rectify a sticking odometer (see other thread) and all was well. However, having put the dash back on something has bappened to the common power line used by all of the dials. The (green) power lines to all of the instruments are receiving about 2.7V instead of 12-14, with the result that everything except the rev counter shows zero, and even the rev counter doesn't ever get above about 500 :-(
My first thought was the common ground, but checking these against the dash illumination supplies showed they were fine. It's definitely the constant power feed.
All of the lines are linked to a common supply, which is part of the three connector blocks in the centre of the under-dash area, near the windscreen. This shows 2.7V on both sides, so it's not a problem there. However, the supply to the alarm remote unit (again, green cable) is a healthy 13V, so it's fine. For now I've patched this in so that I could get back to my flat (was visiting parents).
I know the dials were OK after I'd fixed the odometer, and immediately before putting the dash top back on, so although it's probably related to replacing the dash, it's not likely to be a side-effect of anything else.
Firstly, does anyone know where the two supplies separate, or where the faulty power lines are routed?
Secondly, on an off chance, has anyone else had this? If so, how did you fix it?
Finally, HELP! :-)
Took the dash top off earlier to rectify a sticking odometer (see other thread) and all was well. However, having put the dash back on something has bappened to the common power line used by all of the dials. The (green) power lines to all of the instruments are receiving about 2.7V instead of 12-14, with the result that everything except the rev counter shows zero, and even the rev counter doesn't ever get above about 500 :-(
My first thought was the common ground, but checking these against the dash illumination supplies showed they were fine. It's definitely the constant power feed.
All of the lines are linked to a common supply, which is part of the three connector blocks in the centre of the under-dash area, near the windscreen. This shows 2.7V on both sides, so it's not a problem there. However, the supply to the alarm remote unit (again, green cable) is a healthy 13V, so it's fine. For now I've patched this in so that I could get back to my flat (was visiting parents).
I know the dials were OK after I'd fixed the odometer, and immediately before putting the dash top back on, so although it's probably related to replacing the dash, it's not likely to be a side-effect of anything else.
Firstly, does anyone know where the two supplies separate, or where the faulty power lines are routed?
Secondly, on an off chance, has anyone else had this? If so, how did you fix it?
Finally, HELP! :-)
It appears that the boot release is also affected - with my patch cable in place the boot release is fine, but without it there's no action.
Following on from this I've located another collection of connector blocks by the bonnet release lever. It doesn't appear that these are the problem. There seems to be a second triplet of connectors on the passenger side, tucked up near the windscreen wiper motor, which I've not yet had chance to test.
Does anyone know which way the power line runs along the dash: is the source at the passenger side or the drivers side? In other words, as I trace the wires, in which direction should I be looking for the fault. I've tried disconnecting the block in the middle of the dash, but that left both sides showing about 0.4V versus about 1.5V (now) when connected...
There's certainly something odd going on. Any ideas?
Following on from this I've located another collection of connector blocks by the bonnet release lever. It doesn't appear that these are the problem. There seems to be a second triplet of connectors on the passenger side, tucked up near the windscreen wiper motor, which I've not yet had chance to test.
Does anyone know which way the power line runs along the dash: is the source at the passenger side or the drivers side? In other words, as I trace the wires, in which direction should I be looking for the fault. I've tried disconnecting the block in the middle of the dash, but that left both sides showing about 0.4V versus about 1.5V (now) when connected...
There's certainly something odd going on. Any ideas?
Deliberately didn't disconnect the battery so as to avoid any hassles with alarm, etc: no personal worries at any voltage away from the HT leads, and careful and confident enough to not be overly concerned about accidental shorts.
With the engine not running I get 0V on the power lines, and with it on it's in the 1-3V range, depending upon wihch time I've measured it, so I'm convinced that it's a dodgy connection or damaged wire. I'm just praying that it's not the latter...
With the engine not running I get 0V on the power lines, and with it on it's in the 1-3V range, depending upon wihch time I've measured it, so I'm convinced that it's a dodgy connection or damaged wire. I'm just praying that it's not the latter...
Just a quick update for the benefit of anyone searching the archives. Problem identified and solved.
If the dash power and boot release go, do like I did and check the fuse. If it looks OK, replace it anyway, just to see. That way you won't spend hours tracing wires, hanging upside down in footwells and scratching your head. Arse.
Only re-checked fuse once I found mirror adjustment was out as well - seemed too much of a coincidence, and was. Never mind...
If the dash power and boot release go, do like I did and check the fuse. If it looks OK, replace it anyway, just to see. That way you won't spend hours tracing wires, hanging upside down in footwells and scratching your head. Arse.
Only re-checked fuse once I found mirror adjustment was out as well - seemed too much of a coincidence, and was. Never mind...
as someone who's spent a few evenings upside down with a multimeter, I know how you feelGassing Station | Chimaera | Top of Page | What's New | My Stuff