99 Taco Headlights Don’t Work Except Manually
#1
99 Taco Headlights Don’t Work Except Manually
Hi,
I'm new here and I'm hoping that someone can help me out with this problem with my headlights. It's been ongoing for a while, it started off being intermittent but I now feel safe saying it's totally broken.
Both headlights are out except when I pull in the controller stalk as if I was just flashing my headlights. Then it seems that 1 filament of the high beams turns on. So I've replaced the bulbs, the controller and the relay. The fuses are fine. I've cleaned the ground contact where the battery connects to the body. I checked the wires with a test light, all 3 wires show ground. I borrowed a multimeter from a neighbor. It shows 0 resistance on 2 of the wires (as in the needle pegs to 0 as if I were just touching the probes together). I'm not sure how to test for voltage on this meter.
I'm obviously neither a mechanic nor an electrician so I need some assistance if anyone has any thoughts, experience, or ideas about this problem.
Thanks in advance for any advice.
I'm new here and I'm hoping that someone can help me out with this problem with my headlights. It's been ongoing for a while, it started off being intermittent but I now feel safe saying it's totally broken.
Both headlights are out except when I pull in the controller stalk as if I was just flashing my headlights. Then it seems that 1 filament of the high beams turns on. So I've replaced the bulbs, the controller and the relay. The fuses are fine. I've cleaned the ground contact where the battery connects to the body. I checked the wires with a test light, all 3 wires show ground. I borrowed a multimeter from a neighbor. It shows 0 resistance on 2 of the wires (as in the needle pegs to 0 as if I were just touching the probes together). I'm not sure how to test for voltage on this meter.
I'm obviously neither a mechanic nor an electrician so I need some assistance if anyone has any thoughts, experience, or ideas about this problem.
Thanks in advance for any advice.
#2
Registered User
Testing for ground, means low ohm/resistance readings on the meter. Usually 0.4 or less, someone can correct and try to shame me while they're at it. No such thing as ground value of exact 0, just close. Always resistance. But to protect the electronics, you have to test with the circuitry off (ignition off). Hard to pinpoint without a wiring diagram. Safe bet is if you see a black wire you could check that for ground with the meter.
Testing for voltage has its pros, as you could touch any of the headlight wires and 12 volts or close to is what you should get on one of them when the ignition is on ACC with the headlight switch on. Again, best to search for a wiring diagram or hopefully one of the gurus on here can magically upload for you, so you can test more precisely. But it is a simple circuit, so you could probe a bit and still stay on point.
Just be careful that the probes dont touch hot wires (meaning live even while engine off) or high current ones like battery, or get caught up near moving parts. And dont touch both probes to the same wire. Helps to read the manual on the meter and there's good info here and online on operating.
There's some good reading here in the other forums, though on different model yrs, but the idea is basically the same.
Are you sure you replaced the low beam bulbs with the correct type? Usually a headlamp housing will have separate bulbs for highs and lows. And recheck them fuses. You never know during the whole troubleshooting when they happen to blow right as you're checking stuff.
Hopefully just a couple bulbs.
Welcome to YT.
Testing for voltage has its pros, as you could touch any of the headlight wires and 12 volts or close to is what you should get on one of them when the ignition is on ACC with the headlight switch on. Again, best to search for a wiring diagram or hopefully one of the gurus on here can magically upload for you, so you can test more precisely. But it is a simple circuit, so you could probe a bit and still stay on point.
Just be careful that the probes dont touch hot wires (meaning live even while engine off) or high current ones like battery, or get caught up near moving parts. And dont touch both probes to the same wire. Helps to read the manual on the meter and there's good info here and online on operating.
There's some good reading here in the other forums, though on different model yrs, but the idea is basically the same.
Are you sure you replaced the low beam bulbs with the correct type? Usually a headlamp housing will have separate bulbs for highs and lows. And recheck them fuses. You never know during the whole troubleshooting when they happen to blow right as you're checking stuff.
Hopefully just a couple bulbs.
Welcome to YT.
Last edited by 75w90mantraN; 09-28-2018 at 05:06 PM.
#3
Thanks for this info. It's not a digital multimeter so it just looks like 0 to me. I can recheck in the daylight.
The lights on this truck are a switched ground so it's not that simple to me. Simple for me is just positive and negative like speakers, lol.
The bulbs have worked properly, remember, it's been intermittent, but I changed them again a couple days ago, just to be safe. I would think if they were the wrong bulbs I'd at least have low beams or high beams? I'm just guessing, I could be wrong about that also.
Ok, at least I have a few more things to check. Thank you.
The lights on this truck are a switched ground so it's not that simple to me. Simple for me is just positive and negative like speakers, lol.
The bulbs have worked properly, remember, it's been intermittent, but I changed them again a couple days ago, just to be safe. I would think if they were the wrong bulbs I'd at least have low beams or high beams? I'm just guessing, I could be wrong about that also.
Ok, at least I have a few more things to check. Thank you.
#4
Registered User
In the absence of a wiring diag, you could try tracing the bulb connector wiring to a possible chassis ground, if no insulation getting in the way...and check if any corrosion/dirt at the grounds there, or breaks along the wiring.
Any other electrical issues, they can be possible suspects too, depending on what they are.
Any other electrical issues, they can be possible suspects too, depending on what they are.
#5
This wires are all encased in a corigated plastic tubing which looks to be in good shape, no pinching or splitting. The grommets that protect it though the firewall are in good shape as well.
The question about other electrical issues is a good one. My power door lock on the drivers side doesn't work anymore. The passenger side does work so I just assumed the drivers side has worn out. Maybe they have a ground in common?
I'll see what I can find. It would be great to have some pictures of were the ground straps are located.
The question about other electrical issues is a good one. My power door lock on the drivers side doesn't work anymore. The passenger side does work so I just assumed the drivers side has worn out. Maybe they have a ground in common?
I'll see what I can find. It would be great to have some pictures of were the ground straps are located.
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