Dash fuses help please

[l6rth]

Hi all,

Thought this problem was fix but it's not, for some reason the 15amp dash fuse keeps blowing, not sure why doesn't seem to anything obvious. What possibilities are there? I need to get this fixed as soon as poss as I'm doing thunder in the tunnels (I hope )

Thanks in advance

Rob

[spend]

Often it can be a heater fault that blows the dash circuit, try a new fuse & avoid using the heater blower to isolate that possibility?

[murphster]

spend said:

Often it can be a heater fault that blows the dash circuit, try a new fuse & avoid using the heater blower to isolate that possibility?

Agree with the above. I had the same problem. Once I replaced the heater fan/blower it fixed the dash circuit blowing.

[l6rth]

Heater not on, new fuse as soon as I turn the key I can hear the fuse blow. Any other ideas?

[spend]

Pull the spade terminal off the back of the alternator to see if the dash light circuit is what's blowing it?

You could try pulling all the relays and see if the fault persists I think some models had the switch side powered by the dash (ig switched) fuse but unusual.

Failing that I'd guess its dash top off & start straining for access to investigate by looking / multimeter / isolating gauges instruments... (once its off try flipping the dash facia forward so you can see what you're doing ~ still fiddly)

You still cant rule out the heater if the control box (on all but very early cars) is burnt out BTW they can still fail in the switched off state.

[l6rth]

I'm thinking it may be the heater, changed fuse and removed relays and disconnected a blue connector with 2no small cables connected to it. Then 1 by 1 reconnected and fitted relays, all seemed ok until I touched the heater switch and it blew. Left all reconnected and changed fuse with heater off and switched key on and it blew straight away again without touching heater knob. Is the blue 2 cabled connector for the heater, if not which one is it I can see anything obvious?

Thanks

Rob

[l6rth]

Investigated deeper to try and find the heater control box but I can't find it, also I don't seem to have a ribbon cable I have heard about so does this mean I don't have a heater control box or a/c? I have dash top off and light button panel out had my head in the passages footwell and I just can't find it, the reason I'm trying to find it is I think the fan is blowing the dash fuse.

Thanks

Rob

[spend]

If you just have the wiring going direct to the back of the blower switch then pull the green lead off to completely isolate the blower, and retry the fuse.

In the case of early blower control that is the only power link to the heater from the dash circuit AFAIK (and you should be able to see easily where it meets the rest of the dash 'green bunch').

[l6rth]

Tried that and it still blows, someone said disconnect the spade connector from the alternator but I can't see one but also the fuse blows before I turn the engine over? I have now disconnected nearly every connector and turning the key and I have the same problem, any other ideas?

[spend]

Its the small sense wire on the back of the alt, it is a ring terminal on the serp alt ~ just me always visualizing it as a spade

Its the other end of the charge LED in case you have tried disconnecting that already (trickier than it sounds because of the resistor in parallel with the LED).

Most of the dash & gauges can be isolated by pulling apart the multi-connectors (roughly located behind the heater controls).

[l6rth]

Hi spend, finally found issue thanks to the help of alex daredevils again, the bracket holding the oil pressure gauge had come loose touched the positive and shorted out on the Ali dash, easy fix thank god. Thanks for all your help. It never stops amazing me how helpful Tvr owners and this forum are.

[spend]

l6rth said:

Hi spend, finally found issue thanks to the help of alex daredevils again, the bracket holding the oil pressure gauge had come loose touched the positive and shorted out on the Ali dash, easy fix thank god. Thanks for all your help. It never stops amazing me how helpful Tvr owners and this forum are.

Are the insulating shrouds missing from the spade terminals, they should normally be pretty well protected from that sort of problem IME.

[Alexdaredevils]

spend said:

Are the insulating shrouds missing from the spade terminals, they should normally be pretty well protected from that sort of problem IME.

The plastic threads holding the gauge bracket had broke from a bump or and over tighten by previous owner, causing it to jump about and short out