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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: 83k10silveradooo on November 02, 2021, 01:14:36 AM
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First off, I wanted to say thank you for adding me to the community.
My problem is that, I have no power on the turn signal fuse or flasher. I traced the brown wire from the turn signal fuse on the fuse block, to the ignition switch, and that brown wire has no power. Brand new ignition switch, the truck will turn over and run so I know that at least part of the ignition switch works.
I have headlights, taillights, marker lights, brake lights work, but can't for the life of me figure out why there's no power to the turn signals. Headlights and taillights are both LED, and I bought LED flashers for the hazards and turn signals.
Turn signal switch is brand new as well. Any help is appreciated, thank you
1983 Chevy k10, 350sbc 4 bolt main
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Does the truck have an OEM or aftermarket cabin wiring harness? The OE brown wire from the ignition switch is accessory power. The turn signals are powered by the ignition circuit. Is there power in the IGN tap cavities along the left side of the fusebox?
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Sorry, I should have added this info in my original post. the truck has an aftermarket wiring harness, where there is no bulkhead connector. As for testing the fuse box, I wont be able to until Thursday.
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So the correlation between the OEM and aftermarket wire color scheme, if any exists, maybe happenstance.
Unplug the ignition switch and inspect the plastic floor from which the switch terminals protrude. Each terminal should be identified (e.g., BAT1/2/3, IGN1/2/3, ACC, GRD1/2, SOL). Draw a map view of the terminal layout and note what color wires connect to each terminal. Generally, there are two B+ feeds coming into the switch from the battery, 2-3 ignition out, one accessory out, one starter solenoid out, and two switched ground terminals. The turn signals will be powered by either the IGN1 or IGN2 terminals; IGN3 is reserved for appliances that require power in the ignition switch "run" and "accessory" positions, but not in the "engine crank" position, for instance, power windows and A/C. To which terminal does the turn signal fuse connect?
As you work, you can compare the aftermarket harness to the OEM 1983 Wiring Manual (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/ST386_83_1983_GM_Wiring_Manual_CK_P_G_10_to_30_and_ST.pdf) to determine just how much deviation exists.
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Any help is appreciated
Ignition switch wiring
Orange- Ignition switch acc
Red- Ignition switch power splices off to a Black wire for other ign switch connector
Pink- IGN switch coil
Purple- IGN switch start
Brown- Has no markings on wire but runs from Ignition switch to turn signal fuse which then jumps to the flasher, and the flasher jumps to the turn signal switch
The new ignition switch has no markings, but the old one
Terminals are marked G-I G-2 B1 B2 B3 S A I-1 I-5
Top left is pink top right is brown middle is red bottom left is purple on white connector, middle bottom is orange left is black on black connector
Pink is I-1 brown is A red is B-2 purple is S black is B-3 Orange is I-5
I figured out part of the problem, my truck is technically a 76 but the previous owner swapped everything over too 83, I originally thought it was an 82 so the wiring harness it it is 79-82 but the column is 83 so I swapped the orange and brown wire, now I have power to the turn signal fuse and flasher, but still no turn signals.
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There is power on the turn signal fuse and it jumps across to the flasher but the connector at the top of the flasher connector has no power on it to feed the turn signal switch
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Replace the flasher.
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ok maybe the flasher is defective, it's brand new but ain't nothing unheard of. I will try that thanks
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Remove the old flasher, replace it with a wire jumper between the fusebox terminals and see whether the turn signals illuminate constantly when selected using the turn switch.
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My first LED flasher was "heavy duty", meaning minimum 2A, max 20A. What was I thinking? These LED measure in the milliamp. I found a different flasher for really low amps and it works great now.
Sent from my SM-G965U using Tapatalk
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Could you please link the flashers you bought?
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I was afraid you'd ask that... I found it (I order from all over the place).
Optronics Optronics LED Flasher | OPT ALEDFBP | Qty: 1
From oreilly.
Mark
Sent from my SM-G965U using Tapatalk
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Thank you sir, I will look into it if these flashers I order a couple days ago don’t work
I appreciate it
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FYI I ended up having trouble with my flashers after i went 100% LED. With one incandescent bulb in, it worked fine. The LED vendor suggested I use their flasher since it has a relay embedded. If you have trouble, you can check this out. I ordered 2, one for the turn, one for the 4-way hazards.
https://upcarparts.com/electrical/flashers-modules-resistors/led-flasher-with-polarity-reversing-adapter-12v-90652
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You said it works with an incandescent bulb (original bulb). The LEDs may require a heavy duty harness with relays as does some headlamps.
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Thanks Mike,
I should know better. I've worked on these types of bugs in our computer servers. You turn something off and the circuit load doesn't decay the voltage fast enough to get it below the trip threshold so it doesn't actually turn off. Or half the parts turn off and the other half don't and the system hangs. Sometimes you give it more time, sometimes change the circuit, sometimes add a load resistor. Using the digital voltage meter gave me that answer after talking to the service rep. The guy says 0V, but I know from the meter that the trip voltage is somewhere around 3V, which is very reasonable for a noisy automotive environment. I'm not certain why changing from a transistor to a relay would make a difference here since there seems to be some current bleeding from somewhere. Hmmmm, I've got a few theories, but can only confirm with an oscilloscope. Ok, now i've got to look for a new o-scope to get the waveform. What's an EE without a scope? Always an excuse to get one. Wow, just looked them up, there are lots of options reasonably priced. Will get some pictures and post in a few weeks.
Mark
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Thank you all for the help. I now have turn signals and hazards working. I ended up using these flashers CEC Industries 12V Heavy Duty 2-Pin Electronic Flasher EF32 Relay for LED and Incandescent Bulbs (1-Pack) https://www.amazon.com/dp/B0031GYS6W/ref=cm_sw_r_cp_api_i_J1VBEDTRS280WYE3MF6C?_encoding=UTF8&psc=1 Started my truck up last weekend for the first time in a year, only to find out I have no forward gears working on my transmission. Time for a rebuild, you win some you lose some.