Rx7 FC 1986 : dash light not working.
08-30-22, 04:12 PM
#1
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Rx7 FC 1986 : dash light not working.
Hello everyone.
First of all, english is not my firt language, so sorry in advance if i make a lot of spelling or gramatical mistakes.
So I've been trying to fix my dash light for a while. I've read a lot of pages on this forum to verify what was the problem but i still didn't find it.
When switch the headlights on, the dashboard doesn't light up. I checked the bulbs, i didn't find any burned cables, and the switch seems to be working (i made a continuity test between the white/green and red/green when i turn the switch it works).
the fuse is a problem, it was burned, i changed it, it burned again.
After searching, i saw that it was maybe a TNS relay problem that controls the dash lights and rear lights. Apparently the previous owner bypassed the rear lights control to be constantly on. That logically narrows the problem to the TNS. But i can't find anything about this relay and where to buy a replacement.
Does anyone have a additional idea on what could be wrong, or does anybody know where i can find this rellay ?
Is it possible to bypass the dash light to be constantly on like the rear lights ?
Thank you in advance for the response.
Cheers.
First of all, english is not my firt language, so sorry in advance if i make a lot of spelling or gramatical mistakes.
So I've been trying to fix my dash light for a while. I've read a lot of pages on this forum to verify what was the problem but i still didn't find it.
When switch the headlights on, the dashboard doesn't light up. I checked the bulbs, i didn't find any burned cables, and the switch seems to be working (i made a continuity test between the white/green and red/green when i turn the switch it works).
the fuse is a problem, it was burned, i changed it, it burned again.
After searching, i saw that it was maybe a TNS relay problem that controls the dash lights and rear lights. Apparently the previous owner bypassed the rear lights control to be constantly on. That logically narrows the problem to the TNS. But i can't find anything about this relay and where to buy a replacement.
Does anyone have a additional idea on what could be wrong, or does anybody know where i can find this rellay ?
Is it possible to bypass the dash light to be constantly on like the rear lights ?
Thank you in advance for the response.
Cheers.
Last edited by Tallseal; 08-30-22 at 04:14 PM.
08-30-22, 11:39 PM
#2
Welcome to the club. For clarity, it would help if you tell us if your car is a European spec one or if it is US/Japan spec. European ones have wiring and switches for the Rear Fog Lamps, while US/Japan models do not. With that said, the following applies to US/Japan and may be slightly different from a European model. Having the VIN number would let me confirm what region your car is from.
In the first position, the Headlight switch supplies 12v power to two outputs. One Fixed 12v for things such as the Tail Lights and Storage Box lights, and one Variable 12v that goes through the Dimmer Rheostat (Panel Lamp Control in the workshop manual) for the dashboard lights. I believe they are Red/Blue (fixed) and Red/Green (variable), but please check the Wiring Diagrams on Foxed.ca as it has been a few months since I looked. Also, please note that the manuals there are the North American ones. Plus, my recall of tracing these circuits may be slightly inaccurate as the last time I did so was almost 10 years ago.
If the 12v Variable output is blowing the fuse, you have a short circuit. With the battery disconnected, try testing for continuity between Red/Green and Ground at the Headlight Switch connector. This will read the resistance in the entire circuit, including the bulb filaments (most are #194 bulbs I think), so disconnect or remove them too. In these conditions, if you see a reading of under 5 ohms between Red/Green and Ground, you have a short circuit in the Red/Green wire. With battery and all bulbs removed, it should be Infinite ohms.
Ohm's Law is your friend.
In the first position, the Headlight switch supplies 12v power to two outputs. One Fixed 12v for things such as the Tail Lights and Storage Box lights, and one Variable 12v that goes through the Dimmer Rheostat (Panel Lamp Control in the workshop manual) for the dashboard lights. I believe they are Red/Blue (fixed) and Red/Green (variable), but please check the Wiring Diagrams on Foxed.ca as it has been a few months since I looked. Also, please note that the manuals there are the North American ones. Plus, my recall of tracing these circuits may be slightly inaccurate as the last time I did so was almost 10 years ago.
If the 12v Variable output is blowing the fuse, you have a short circuit. With the battery disconnected, try testing for continuity between Red/Green and Ground at the Headlight Switch connector. This will read the resistance in the entire circuit, including the bulb filaments (most are #194 bulbs I think), so disconnect or remove them too. In these conditions, if you see a reading of under 5 ohms between Red/Green and Ground, you have a short circuit in the Red/Green wire. With battery and all bulbs removed, it should be Infinite ohms.
Ohm's Law is your friend.
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