Small electrical problem??

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JerryL770
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#1 Small electrical problem??

Post by JerryL770 » Tue Mar 15, 2022 5:38 pm

I have fitted a low oil pressure warning light with the pressure switch Tee'd on above the oil filter.

I decided that instead of having a separate light, I could combine it with the choke warning light. So I arranged for the oil switch to provide an earth and ran the old white/brown oil pressure signal wire to the light with a separate power supply for this from Fuse 7. The choke warning light power seems to come from a green to the switch, through the light to a separate earth. This was working fine till the 2A fuse I have in the oil light switch power supply failed for some reason. A lot of faffing about till I found that, fixed it and the oil light works, but now the choke light has failed and there is no power to the switch from the green wire which disappears into the back of the dash to who knows where. The problem with this is that I cannot find the choke light/switch indicated in the Coventry Auto Components wiring diagrams anywhere :questionmarks:

Advice appreciated, thanks.
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT - now gone :sad:

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DWW
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#2 Re: Small electrical problem??

Post by DWW » Tue Mar 15, 2022 6:27 pm

It is difficult to quite follow how you went about this mod. My only suggestion is to revert back to stock, find whether the fault still exists, diagnose and fix and then re-think the mod. On yor legend what was the blown fuse powering?
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR
"Experience is something you don't get until just after you need it."

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rswaffie
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#3 Re: Small electrical problem??

Post by rswaffie » Tue Mar 15, 2022 6:29 pm

Hi Jerome
In terms of the Coventry diagrams, have you looked at the colour wiring diagram in the kb - it shows the switch/lamp.

https://www.dropbox.com/s/dx7f9jvz6pvca ... r.jpg?dl=1
Richard

Previous owner and restorer of a S1 3.8 FHC Opalescent Golden Sand with Tan Trim 889504 (now sold and headed for Athens)

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MSM
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#4 Re: Small electrical problem??

Post by MSM » Tue Mar 15, 2022 6:34 pm

Try page 3 and page 7 top right hand corner!!
Mike

1969 S2 FHC

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JerryL770
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#5 Re: Small electrical problem??

Post by JerryL770 » Tue Mar 15, 2022 6:37 pm

Stupid of me really.

Think I did as you suggested and looked at the main fuses and 7 is blown. I must have allowed a short circuit whilst having both hands inside the dashboard. :oops:

New 35A fuse has sorted it.
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT - now gone :sad:

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JerryL770
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#6 Re: Small electrical problem??

Post by JerryL770 » Tue Mar 15, 2022 6:39 pm

MSM wrote:
Tue Mar 15, 2022 6:34 pm
Try page 3 and page 7 top right hand corner!!
Absolutely right thank you. I did not look there assuming it would be shown on one of the detail pages.
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT - now gone :sad:

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Series1 Stu
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#7 Re: Small electrical problem??

Post by Series1 Stu » Tue Mar 15, 2022 10:29 pm

JerryL770 wrote:
Tue Mar 15, 2022 6:37 pm
Stupid of me really.


New 35A fuse has sorted it.
Rule 1 of poking about behind your dashboard - Always disconnect the battery earth before you start. There are so many risks involved in electrical work. Keep yourself and your car safe.

Regards
Stuart

If you can't make it work, make it complicated!

'62 FHC - Nearing completion
'69 Daimler 420 Sovereign
'93 Jaguar X300 XJR basket case
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lowact
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#8 Re: Small electrical problem??

Post by lowact » Wed Mar 16, 2022 6:58 am

Couldn't understand yr explanation, hoping you did it like this ...
Image
Regards,
ColinL
'72 OTS manual V12

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JerryL770
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#9 Re: Small electrical problem??

Post by JerryL770 » Wed Mar 16, 2022 10:27 am

lowact wrote:
Wed Mar 16, 2022 6:58 am
Couldn't understand yr explanation, hoping you did it like this ...
Image
Thank you Colin. It has taken me a lot of head scratching to try to get this working and your diagram shows me how I've got it only half right and probably why my fuses are blown. Possibly because I was changing it from 2 separate circuits/lights to the one light/divided earths circuit that I should have done. Possibly because the Jag circuit takes the choke light power to the switch, then light and earth and I was adapting the wiring to try to suit. I really confused myself!

I shall hastily re-arrange the wiring after I disconnect the battery, another salient point.

Thank you both.
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT - now gone :sad:

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