Elec gurus: 69 2L blinker question on diagnostic methods

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FergO2k
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Elec gurus: 69 2L blinker question on diagnostic methods

Post by FergO2k » Mon May 13, 2019 2:37 pm

Greetings all.
69 2L with GM alt conversion. Underhood wiring harness section replaced when gross PO conditions were discovered.

Rear blinkers currently in-operative (and both went at once).

First off, I have always been un-successful at getting blinkers to respond unless engine is running. Common?
(really makes it a pain to work inside, as then the garage really smells)

ANyway, some brilliant PO in the past rattle canned the trunk area, but didn't do even the cheapy wiring mask job (squish tin foil around them) so all the wires are painted black. Moving things around in the trunk and little excess length means they have come come out several times, and sometimes may have gone in swapped, because folks on our backroads drives say, "Fergus, you running lites are on at nite, but when you brake, 3 of the 4 get brighter and the 4th turns off." (meaning it was grounding thru a power wire, until that wire has power applied, and that turns off the bulb)

So, first off I am going to try and "re-expose the wire colors" using mineral spirits or other chemical solutions.

But short of that, turn on car, put on blinker, put in test light, and just keep poking until power is found?

Any tricks?

Full disclosure, I also have one dim headlite, and it ain't the bulb, so will be checking front end grounds too.
(note: I pulled the headlite switch and cleaned all contacts... but that was now 10-12 year ago, so the grundge may have returned)
69 hedlights are "ground switched" not "power supply switched" correct? (or did I just hear that from the peanut gallery?)

Thanks for the assistance,
Fergus O'FuseFry
Fergus O
69 2L, SUs (driver, not susceptible to polish)
02 Tacoma 4 door
Los Alamitos, CA

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Linda
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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by Linda » Mon May 13, 2019 3:04 pm

While waiting for gurus, I 'm guessing the turn signal flasher died or has a bad ground?
I converted to 1970 connector rear light harnesses for a more secure connection, as the bullet connectors were getting loose.
Linda
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Los Angeles, CA
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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by FergO2k » Mon May 13, 2019 3:09 pm

Hmm, thought maybe that would be, but (memory fails me) aren't there two of those in the drivers footwell?
Maybe I had a fuse blow or surge and blew both at once?
Front blinkers are still working though, and I think both run off the same blinker can. (they must, the two are for R/L, not front back... I think)
yep, one wire coming in to the can and one leaving, as has to be RH side and LH side, and exiting power then gets split.
Fergus O
69 2L, SUs (driver, not susceptible to polish)
02 Tacoma 4 door
Los Alamitos, CA

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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by fj20spl311 » Mon May 13, 2019 3:42 pm

Are you sure you have "69-70" wiring. 9 prong turn signal wiring?
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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by fj20spl311 » Mon May 13, 2019 3:47 pm

IIRC, it can be in hazard switch, t/s or wiring. You are correct that the usual cause of a light going off is a bad ground.
I suggest you print out a large version of the wiki color 69-70 wiring diagram. Mine is 5x5 landscape pages taped together.
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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by FergO2k » Mon May 13, 2019 3:51 pm

Hmm, will check that pronto.
Fergus O
69 2L, SUs (driver, not susceptible to polish)
02 Tacoma 4 door
Los Alamitos, CA

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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by fj20spl311 » Mon May 13, 2019 4:08 pm

On a 69-70, the t/s flasher FUSE is powered through the IGN switch. The Hazard flasher Fuse is powered directly from the battery.

You should check with a volt meter, but it looks to me that if you disconnect the "green" wire from the flasher and run a hot from the Hazard Fuse it should allow you to test the circuit without the engine. Do not leave it that way because it bypasses the disconnection of green wire 4 to green wire 5 when the hazards are on...both flasher at the same time.
Phil
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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by FergO2k » Mon May 13, 2019 4:25 pm

Great, thanks Phil, that is a huge simplification of the diagnostic activity.
Fergus O
69 2L, SUs (driver, not susceptible to polish)
02 Tacoma 4 door
Los Alamitos, CA

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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by fj20spl311 » Mon May 13, 2019 5:29 pm

FergO2k wrote:
Mon May 13, 2019 2:37 pm

Full disclosure, I also have one dim headlite, and it ain't the bulb, 69 hedlights are "ground switched" not "power supply switched" correct?

Thanks for the assistance,
Fergus O'FuseFry
Correct about ground switched. The lights are linked before relay and then to ground, therefore if its just one beam on one side, its in the plug at the headlamp blub, a connector in the ground wire before the relay. If its in both beams on one side, its could be in the wiring connector, but I would bet on the connector at the blub or low voltage to the H/L.
With the headlamps on test the hot voltage.
Jumper the other two to ground one at a time to ground. If it bright with the jumper, its in the ground wires before the relay.

If one headlamp is bright and one is dim the ground to the relay should be good.
Phil
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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by Curtis » Mon May 13, 2019 7:43 pm

66 stroker
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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by FergO2k » Sun Jun 16, 2019 11:17 am

Many thanks to all for all the helpful suggestions and support.
“It takes a village.”

Diagnostic award for dim headlines goes to Phil in SD, as one of the 3 slide ones had rattled a bit loose. (And in dismantling, who knew that the chrome trim rings attracted and secreted such mulch of dead bees!)

In terms of rear blinkers, I am part way there.
Lower left lite out is now common, and re-lites when twisted 1/8 inch in its socket.

Current status:
Rear Blinkers only work when parking or headlines are on. (Fronts work always)
Truthfully, the rear blinkers seem to create such a draw on voltage that all 4 rear blinkers throb equivalently, but what the heck, better than nothing and absolutely drivable. (On recent backroads drive, I just clicked on parking lites whenever entering a town, easy solution)
The quest continues, thanks to all, updates will continue.
Fergus O
69 2L, SUs (driver, not susceptible to polish)
02 Tacoma 4 door
Los Alamitos, CA

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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by mraitch » Sun Jun 16, 2019 2:27 pm

what about brake lights - do parking/heads have to be on??
One of the cans under dash is definitely blinker. Check when driver side door is open - is there either a hole or a push button. if so the other can is likely door buzzer, though i didn't think these were on other than '70
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Re: Elec gurus: 69 2L blinker question on diagnostic methods

Post by Curtis » Sun Jun 16, 2019 4:15 pm

There should be two flasher cans mounted in the driver side foot well on the side wall.
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