Troubleshooting Non-Functioning Instrument Lights

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nightcrawler07
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Troubleshooting Non-Functioning Instrument Lights

Post by nightcrawler07 »

Fuses all seem good, I pulled the instrument cluster and cleaned it, checked the bulbs, the works. The High Beam indicator and both turn signals are working fine. I understand that it could be the wiring, although I am very skeptical of that as everything seems to be in great shape all across the car. I think if anyone has access to a 1984 SR5 wiring diagram, it likely would be the most useful. Any info would be great!
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dlb
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Re: Troubleshooting Non-Functioning Instrument Lights

Post by dlb »

Is it just the lights in the dash cluster? I can't remember which fuses are where but there are fuses in a few different locations, have you checked the fuses in each of those? My next guess would be a bad ground, which is always a wonderful PITA.
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rer233
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Re: Troubleshooting Non-Functioning Instrument Lights

Post by rer233 »

Have you checked the rheostat control for the bulbs? Do the illumination bulbs for the heater controls work?
if it aint there, there's a good chance it won't break!
83 SR5 Silver/Blue (Snowmobile/work beater)-totaled but drivable
85 SR5 Blue
88 SR5 White (the 'good' one)-not anymore-totaled
87 fwd silver wagon a/t
87 4wd dx Cream (a/t- not anymore- now m/t)
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dlb
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Re: Troubleshooting Non-Functioning Instrument Lights

Post by dlb »

rer233 wrote: Sat Apr 23, 2022 7:45 am Have you checked the rheostat control for the bulbs? Do the illumination bulbs for the heater controls work?
ooooh, good call. I remember this was the solution for another member having the same problem once.
nightcrawler07
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My tercel:: 1984 SR5
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Re: Troubleshooting Non-Functioning Instrument Lights

Post by nightcrawler07 »

rer233 wrote: Sat Apr 23, 2022 7:45 am Have you checked the rheostat control for the bulbs? Do the illumination bulbs for the heater controls work?
I can't say for certain if the heater control bulbs work or not...the inclinometer bulbs do not, however the dome lights are functional. I'm very intrigued by the rheostat being an issue tho because I noticed that when I put the final few pieces of dash trim on the other day, the rheostat is not lined up in the center of its slot, and additionally I realized that the drivers side dash is not flush with where the heater vents meet, if that makes sense. I suppose I will pull some more screws out tomorrow and keep digging!
nightcrawler07
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Posts: 20
Joined: Tue Feb 22, 2022 12:38 pm
My tercel:: 1984 SR5
Location: Las Vegas

Re: Troubleshooting Non-Functioning Instrument Lights

Post by nightcrawler07 »

dlb wrote: Fri Apr 22, 2022 11:25 pm Is it just the lights in the dash cluster? I can't remember which fuses are where but there are fuses in a few different locations, have you checked the fuses in each of those? My next guess would be a bad ground, which is always a wonderful PITA.
I checked the Fusebox under the drivers side and the one under the hood. I may go back through and check every fuse under the drivers side, as I only checked ones that I though might be remotely relevant to instrument lights.
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dlb
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Re: Troubleshooting Non-Functioning Instrument Lights

Post by dlb »

nightcrawler07 wrote: Sun Apr 24, 2022 1:38 am I can't say for certain if the heater control bulbs work or not...the inclinometer bulbs do not, however the dome lights are functional. I'm very intrigued by the rheostat being an issue tho because I noticed that when I put the final few pieces of dash trim on the other day, the rheostat is not lined up in the center of its slot, and additionally I realized that the drivers side dash is not flush with where the heater vents meet, if that makes sense. I suppose I will pull some more screws out tomorrow and keep digging!
The initial dimmmer knob test is easy -- just turn it! If they don't come on, remove the trim panel and make sure the wires are connected to the back of the dimmer. If the dimmer itself looks suspect like you mentioned, check for voltage both coming in and going out of it.
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rer233
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Re: Troubleshooting Non-Functioning Instrument Lights

Post by rer233 »

Or just connect the dimmer wires together, thereby bypassing the dimmer and the lights should be full bright.
if it aint there, there's a good chance it won't break!
83 SR5 Silver/Blue (Snowmobile/work beater)-totaled but drivable
85 SR5 Blue
88 SR5 White (the 'good' one)-not anymore-totaled
87 fwd silver wagon a/t
87 4wd dx Cream (a/t- not anymore- now m/t)
nightcrawler07
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Posts: 20
Joined: Tue Feb 22, 2022 12:38 pm
My tercel:: 1984 SR5
Location: Las Vegas

Re: Troubleshooting Non-Functioning Instrument Lights

Post by nightcrawler07 »

The issue was indeed the Rheostat. I don't know if it was actually bad or not, but it was missing the plastic female piece of the harness. It appeared as though the terminal prongs were bent out of alignment because of this. I was able to pull a rheostat out of a 2wd tercel at the local junkyard. the instrument cluster looks great!
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NWMO
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Re: Troubleshooting Non-Functioning Instrument Lights

Post by NWMO »

Great job, thanks for letting everyone know.

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