86forrunner22RE

read all the other posts and yes they pretty much are the same but Ive done just about everything except take the harness apart (thats next). I get low beam lights fine and the high beam light on the dash comes on when I flash and move the switch to high beam. the problem is I get no high beam lights when I flash or turn the switch to high beam. Ive checked the light control switch in the truck and out with a battery and its good, I can hear the relay is switching both in and out of the truck. Ive taken another out of a parts truck checked it put it in the truck and it didnt work. Ive checked the head light control relay it checked good and Ive swapped it out still no High beams. Fuses are good and Ive checked the voltage to lights and this is where its fuzzy from memory. Pins 1-2-3 all have 0v when switch is off, pin 1 has 11.84v and pin 2 has 14.22v pin 3 has 1.76v, in high beam pin 1 has 14.43v pin 2 has 14.47v and pin 3 has 14.49v. Im almost positive I have a short but would like to confirm or maybe some one has this problem also and push me in the right direction. Also rear lights, turn signal lights low beam light all work as they should, just no high beam.

UPDATE: Yes Ive switched light bulbs and check to make sure they were good in my other truck. This is where I need help! I checked the voltage in my other truck and Ive narrowed the problem down to wire #2. Other truck shows when in high beam wire #2 should convert to ground and it is not. As stated before all 3 connections are showing 14 volts. To answer another question I took the voltage off the light with the plug connected.

So the question is how come wire #2 reads 14v when it should read ground and doesnt the ground come from the switch that checks good?

Thanks ............ Bill

Windsor

Do you have the FSM? Page BE-14 shows you how to test the headlight control relay.

Also, an off-the-wall question, but have you swapped out one of the headlight bulbs? Is it possible that both high-beams are out?

4Crawler

iTrader: (3)

If you have any headlights (low or high beam) the relay is working fine, all it does is supply power to the common terminal of the bulbs. The problem is likely in the combo (dimmer) switch or the wiring:
- http://www.4crawler.com/4x4/CheapTri...eadlight_Combo

Assuming the bulbs are OK.

Windsor

Yeah, saw that awhile back, I love your write-ups.

Two things he said that made me think it's not the combo switch:
1) no high-beams when pulling the flash-to-pass
2) high-beam indicator comes on

(2) could be non-diagnostic data on Toyota, but my Mazda wouldn't illuminate the high-beam indicator when the combo switch was flaking out.

4Crawler

iTrader: (3)

The indicator works separate of the switch, see the wiring diagram on my page.

Windsor

Ah, you are correct, it's actually a "not low beam" light.

nice.

86forrunner22RE

come on guys and girls (dont want to offend any one) read the write up. Yes I have swapped out the bulbs or light with two known good ones also. I think the clue I have a short is on high beam I get no ground (pin 1 has 14.43v pin 2 has 14.47v and pin 3 has 14.49v) and yes I have been to all your sits and read the writeups thats how I got here and yes I do have a 85 and 86 FSM. Im hoping some has already been here or maybe can confirm my theory of a short and tell me where to start or what to look for.

Thanks ........ Bill

Windsor

Your write-up isn't terribly clear (even after you've edited it a few times today), and I don't see where you say you've swapped out the bulbs in any version of it so far.

Are you checking the voltages with the bulb in the socket? (hint: pull the connector out a hair so that you can poke the bulb-spade with the voltmeter).

4Crawler

iTrader: (3)

Likely an open circuit (lack of connection) rather than a short (a persistent connection) is causing the high beams not to work. It is a connection to ground that makes the high bems come on and if that is missing, no current flows and no light is produced.

86forrunner22RE

UPDATE: Yes Ive switched light bulbs and check to make sure they were good in my other truck. This is where I need help! I checked the voltage in my other truck and Ive narrowed the problem down to wire #2. Other truck shows when in high beam wire #2 should convert to ground and it is not. As stated before all 3 connections are showing 14 volts when in high beam. To answer another question I took the voltage off the light with the plug connected to the light and the light on or off.

So the question is how come wire #2 reads 14v when it should read ground and doesnt the ground come from the switch that checks good?

Thanks ..... Bill

4Crawler

iTrader: (3)

Yes, the switch is the ground connection, so as I mentioned before, you have an OPEN CIRCUIT someplace, that means some connection is broken. Eithe rthe switch contacts are not making contact (as was my problem):

More info:
- http://www.4crawler.com/4x4/CheapTri...eadlight_Combo

Or a connector is not making connection some place or a wire is broken (as I had someone just report they had a loose wire at that combo switch connector).

A.Wilson013

4Crawler,

I have this same problem (I think) I can pull my light switch back toward me, and hold it, and the brights come on. However, when I push it out to make them stay on, they turn all my lights off.

I have tried your Cheap Tricks write-up, however, I cannot find the parts that look like your pictures. Does my 87 SR5 have a different switch than you?

Thanks,
Alex

4Crawler

iTrader: (3)

I doubt you have a significantly different switch. Open up the steering column until you can see the switch that the dimmer stalk activates, that is where the problem likely is. Not, this is not the knob down below where you adjust the brightness of the gauge lights, some folks think since that dims those lights it also does the headlights.

Once you find that switch, see what contacts close when you pull back and what contacts close when you push it forward. Then check those contacts that are different and likely the problem is there.

86forrunner22RE

Ive checked them, cleaned and sanded them. I looked at them while I operated the switch and it appears to work as advertised and I check the switch as the FSM says to and it checked good. Ive swapped out the the whole assembly and I got no high beam so Im going to try and troubleshoot the #2 wire and see what I get. Is their any way to go around the switch to see if it is the switch.

4Crawler

iTrader: (3)

Well if FLASH mode does not work either (I think you said that), it is likely not the switch, since FLASH uses different contacts that HIGH, so unless there is an identical problem in both modes, it is probably a broken wire or loose connector someplace. I understand that there is a connector down along the column that can sometimes come loose. Or try to find that high beam wire back as close to the switch as possible and try grounding it. If the light works, then the problem lies between the point you tested and the switch, if not the problem is forward of the test point. Also check the cab ground screw, behind the driver's side kick panel, screw into the sheet metal with a bunch of ground wires attached.

86forrunner22RE

Thanks I appreciate the help. I hate troubleshooting electrical wires their are so many variables sometimes. I kinda knew I had a short when I found it has 14 volts on all 3 pins. Well if and when I find out what it is Ill post it and maybe someone else needs the info.

4Crawler

iTrader: (3)

Highly unlikely you have a short, you most likely have an OPEN connection some pace that is preventing the current from getting through.

86forrunner22RE

yes I guess you are correct I have a open connection: I dont believe its preventing current from getting through but preventing it to ground because I get 14 volts constant on #2 connection when it should be ground

4Crawler

iTrader: (3)

A circuit needs power and ground to close the circuit and let current flow. The headlight relay supplies power and it is the combo switch that supplies ground. The reason you get power at the high beam pin is that you have 12 volts at the common point and without the ground connection, the other side of the filament has 12 volts as well, and with 12 volts on both sides of that filament, you have 0 volts difference between the sides and since V = I x R, if V = 0 then I = 0. It is only when that ground connection is present can you get current to flow from the battery to the relay to the bulb and finally through that switch and to ground:


http://www.4crawler.com/4x4/CheapTri...l#HarnessTypes

86forrunner22RE

CLOSED AND REPAIRED: Thanks for the help guys. I found the problem and I bet itll be the culprit to others. The problem was a corroded wire on the right hand side about 14 inches from the light plug where its spliced and Y's off to the left hand side. This is also behind the battery. Ive been chasing a ground and all this time and it was red / yellow wire for the high beam. I was getting 14 volts because the read /green wire was feeding it from low beam. In any case the high beams are working and Im happy after 3 days of chasing wires.