355 97 won’t switch off!?

I don’t

I don’t know if it makes a difference but when I bridge the ignition on and switch the lights on (headlights) they stay on even after removing bridge - keeping the ignition on So if the car was running it would stay running until light have switched off - I’m thinking there maybe a melted connection somewhere?

 

Again, to me, it does sound like the red and blue ignition wires are permanently shorted, but as stated in earlier posts, the symptoms also seem to be the same as shorted alternator wires.

To check the ignition lock, simply disconnect the 6 pin plug at the base of the steering column and check the resistance between the red wire and light blue* wire (on the lock side of the 6 pin plug) with the key off. Or have you tried this already? It should be open circuit on a good ignition lock.

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It seems odd, however, that the instrument binnacle is not displaying more lights.

*Not the light blue/black wire.

With the key in the off position, none of those ignition lock wires should be joined together.

 

After more investigation I’ve found the front wiring harness fried - one wire melted back to copper the length of the loom , connecting to wires left right and centre -
Plan is to replace complete front loom I have ordered the loom and the ignition loom , obviously then need to find out what has caused it . Will update with findings after I’ve replaced everything!. Thanks again for your help Ian !

 

Ian would you know what the audible relay controls as it’s now going off and won’t stop when the ignition is on ? No warning lights etc ?

 

Audible relay? You mean the roof buzzer on the spider? If the roof is up, the buzzer can still be triggered if the Airconditioning/Instrument fuse has blown. The fuse also supplies power to the roof and seat switches and some parts of the Roof ECU (and the Roof ECU gets confused and generates the buzzer).

Or do UK cars have the same annoying buzzer as the US cars for the seatbelts/brakes/doors?

 

Check for power on fuse 24 (on the 5.2 car) with the ignition on. This fuse powers instruments (including the Oil Temp in the centre cluster), many dashboard warning lights, the speedometer sensor on the gearbox, the vertical acceleration sensor for the suspension system (and at least some circuits in the suspension ECU)...

I hope this isn't causing your melted wires. It will be very hard to isolate these circuits. If the fuse has blown, kill battery power and see if the fuse is directly shorted to earth (cold side if you can figure out which is hot (ignition) and which is cold (system side)

 

Here's a photo of the relay panel on a 5.2 RHD spider ('98)

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Hi Ian , I found the body of the fuse melted but not severe- somebody has switched it to a 30amp instead of a 10 amp , I have tested and has 11.9v each side of the fuse . Can see any other burnt wires around there at all ? At this stage I’m completely lost I have replace the front loom with success and the ignition loom , now it’s just this beeping and the lack of instruments and seats !

 

Ugh... There may be burnt out wiring downstream of the fuse. There may be a faulty component drawing a lot of current and the wiring (only designed for a 10 amps) may have acted as a fuse rather than the incorrect 30 amp fuse. I guess the next step is to make sure the wiring in your relay panel is ok and then track the wiring downstream of the relay panel.

You can check for voltage at pin A2 on the back of the relay panel. It's not overly difficult to unbolt and look at the back (see instructions below), but rather than doing that, you might want to see if any of the car is receiving your 11.9 volts (other than the relay panel). Anyway, I think I'd eventually want to check out the state of the wiring on the back of the relay panel (especially if the fuseholder is starting to melt).

Prior to all this mess, were there any fault lights? I've read about some really strange faults which have blown that fuse (such as a shorted suspension system accelerometer behind the front bumper).

I'm currently looking for components which use that fuse which are easiest to get to. This could take a while. There are just so many of them. Even the fuel quantity damper unit uses this fuse (on the back of the relay panel). There are a number of splices in unknown locations, but I can group the user systems based on the splices they use.

For example, here is the instrument diagram showing splices 30019 and 30020 (not all wires are shown on the splices). Note that splice 30020 actually feeds splice 30019.

Fig5_Instruments_Handbrake_ABS_5.2(1997~)

Perhaps you could check to see if there is power at the roof and seat switches (you may have to take out the ashtray to access the plugs). Of course, fit a 10 amp or even 5 fuse to keep the current level low.

To remove the relay panel on a Right Hand Drive spider, I find it's best to remove the forward (carpeted) section of the centre console. There are a few bolts and screws involved (including a very long hidden one next to the fuse panel). I usually remove the relay panel cover (2 bolts), then remove the top row of relays, temporarily, to allow more clearance to drop the relay panel. I don't know if the relays are all the same, so mark them before removal. Protect the Bilstein suspension unit with a rag to stop it being scratched. Then...

Undo the single bolt holding the roof buzzer in place (if your buzzer is in the same place as in the photo). The relay panel should then slide to the left (there are locating pins on the right hand side). You should be then able to fold the relay panel downwards by pulling on the top.

Then look for pin A2 and check the voltage on that. Here's a graphic of the back of the relay panel on a RHD car. I've marked pin A2. There should be a green/white wire on it.

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In the diagram, you may be able to see plug 41024. This is the upper white plug to the right of the relay panel in my photograph (above). This may help you to isolate some of the circuits.

Anyway, don't be disheartened. I'm sure your car will be back on the road soon.

 

Here's a list of components running off the Aircon/Instrument fuse splices:

Spice 30020 feeds:

Splice 30019 (see list below)
Fuel Level damper (mounted on the back of the footwell relay panel)
Oil Temp Gauge (centre cluster)
Bistein suspension unit below footwell relay panel
Vertical Acceleration Sensor (07056) on front bumper (via luggage compartment relay panel plugs)
Connector 41024 (to the left of the relay panel on RHD cars) which powers:
Spider roof ECU and roof/seat switches (via splice 30012)
Connector 41019 (behind rear left strut) which supplies power to the speedo sensor on gearbox.


Splice 30019 feeds:
Instrument binnacle (left and right connectors and also individual instruments)
Inside air temperature sensor (near driver's knee)
HVAC Water recirc pump (01406) in forward luggage compartment
HVAC recirc fan control unit (10008) in forward luggage compartment
HVAC relay solenoids (relays 04306 and O4269) in forward luggage compartment.
HVAC ECU (in forward luggage compartment)

Do you know much about the car's history? i.e. previous problems (HVAC, roof control, suspension problems, speedo problems, etc)

Unfortunately, part of your faultfinding may include applying ignition power with the instrument panel disconnected (this will set the airbag light). All things considered, I guess this will be the least of your problems.

 

(EDIT: Deleted my last post because I mixed up my splices).

Rethink:

We know we have lost power to splice 30020 because we have no instruments and the roof buzzer is sounding. So the problem lies between the red fuse and splice 30020. I would check for voltage at the back of the relay panel (pin A2) and check the wiring to the splice 30020 (wherever that is). Here's a photo of the back of the panel on a RHD car.

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