Blinker Indicator Issue

[Kasey 1977 K10]

Hoping someone has some ideas. I have a 1977 K10. All the turn signals work but the interior left signal indicator (green) does not light up. It did this before and after my partial restore. I replaced the gauge cluster housing circuit backing with all new clips and led bulbs. Every light works except the left turn signal blinker indicator and as previously mentioned all the turn signals work as they should. Any ideas?

 

[Georgeb]

What have you tried? Have you veified the light, socket and signal to the cluster.

 

[Kasey 1977 K10]

What have you tried? Have you veified the light, socket and signal to the cluster.

Basically I've only tried what I listed. New circuit and new bulbs. All of the exterior blinkers work and the right indicator light works. Just the left interior indicator doesn't. You can hear the clicking but no blinking light in the cab.

 

[Georgeb]

Check for power on the light blue wire in the plug for the cluster when you have the left signal on. If there is no power present "pulsing on and off with the flasher" your problem is in the wiring leading up to the cluster. If power is present it is an issue with the cluster. Also be sure that connector is good on the plug.

 

[Kasey 1977 K10]

Check for power on the light blue wire in the plug for the cluster when you have the left signal on. If there is no power present "pulsing on and off with the flasher" your problem is in the wiring leading up to the cluster. If power is present it is an issue with the cluster. Also be sure that connector is good on the plug.

Thanks! I'll give those a try. I did replace all of the bulb plugs when I did the circuit and bulbs. Now I have to figure out why suddenly my brake light that has never worked stays on all the time.

 

[Georgeb]

Thanks! I'll give those a try. Now I have to figure out why suddenly my brake light that has never worked stays on all the time.

the warning lamp in the cluster?

 

[Kasey 1977 K10]

the warning lamp in the cluster?

Yes, the red brake light indicator that should only be on when the parking break is on. It never worked before. Then it started coming on when it was cold and went back off when the truck warmed up (maybe a coincidence) but now it stays on all the time.

 

[Georgeb]

Yes, the red brake light indicator that should only be on when the parking break is on. It never worked before. Then it started coming on when it was cold and went back off when the truck warmed up (maybe a coincidence) but now it stays on all the time.

Ok, check that your parking brake pedel is returned fully. You can aslo
Unplug the wire from the proportioning valve in the braking system. It is located on the cross member below and behind the radiator. Report back if the light goes out. If it does not trace the wires looking for a short to ground as best you can.

 

[chengny]

This might have something to do with it:

I replaced the gauge cluster housing circuit backing with all new clips and led bulbs.

Did the LH directional indicator work prior to the installation of the LED's? If so maybe that particular LED was installed backwards in it's socket. Polarity matters with LED's.

 

[Kasey 1977 K10]

This might have something to do with it:

I replaced the gauge cluster housing circuit backing with all new clips and led bulbs.

Did the LH directional indicator work prior to the installation of the LED's? If so maybe that particular LED was installed backwards in it's socket. Polarity matters with LED's.

No, i didn't work with the old circuit, clips or bulb. It was an issue for my dad before as well. He just lived with it.

 

[chengny]

Well, if the exterior front LH turn signal is working right and you are confident that everything in the instrument cluster (associated with the LH indicator) is as it should be... there is only one part of the circuit left to check.

It would appear that there is a problem with the branch lead - that connects the main turn signal feed (which runs from the directional switch to the lamps) to the printed circuit in the cluster:

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Its pretty straight forward. There is a spliced connection located on the cab side of the main harness bulkhead connector block. The two wires are spliced right where the main feed - the one that goes out to the turn signal lamps - enters the block. If you release the fuse block from the bulkhead connector (it is secured by 2 screws - in the upper RH and lower LH corners), and twist it out of the way, you will be able to see the actual splice.

The LT BLU lead from the directional switch transits the bulkhead connector at the 2nd bay from the top, in the outermost column of the connector's middle section. A couple of views showing the splice:

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If the splice appears to be good, test the branch lead a few inches away. Use the tip of your meter probe to pierce the insulation and see if you get the on/off 12 VDC that is apparently available at the splice. If there is no voltage at the test point, look more closely at the splice - it may just look like its connected.

If there is a pulsed signal at the test point, there must either be a break further up in the lead to the cluster - or there is still a problem in the instrument cluster.