Paging Electrical Gurus... (1 Viewer)

[Green Bean]

There is a split-second momentary flash from the dash turn signal when I turn on either heater or activate the high beam. Everything seems to function as it should, but I'm just wondering if I need to track this down. The only fairly recent change is I installed led bulbs in the dash lights. Any ideas?
Thanks.

 

[charliemeyer007]

I think something is going bad in the ignition, heater or high beam switches. Intermittent shorts are really hard to find. Someday the magic smoke will be let out and the issue will be reveled.

I'd keep a good assortment of fuses, some wire, electrical tape & connectors plus the tool on hand. A copy of the wiring diagram is good. Being able to hot wire it should get you home.

 

[45Dougal]

There is a split-second momentary flash from the dash turn signal when I turn on either heater or activate the high beam. Everything seems to function as it should, but I'm just wondering if I need to track this down. The only fairly recent change is I installed led bulbs in the dash lights. Any ideas?
Thanks.

Interesting fault.
The turn signal operates on its own fuse for turn, and the stop fuse for hazards.

Remove each of those fuses and check if it still happens.

I suspect that it may be just inductive coupling between the white wire and your turn signal wire - this can happen when you have two conductors running parallel to each other for a while in the harness, where a very high current surge of turning something on, can couple across to a very sensitive item such as very low current needs of an LED.

If that is the case, you could try separating wires in the harness.
Adding a big ferrite around the white wire (a few turns through it) might be enough to do it.

 

[Green Bean]

Interesting fault.
The turn signal operates on its own fuse for turn, and the stop fuse for hazards.

Remove each of those fuses and check if it still happens.

I suspect that it may be just inductive coupling between the white wire and your turn signal wire - this can happen when you have two conductors running parallel to each other for a while in the harness, where a very high current surge of turning something on, can couple across to a very sensitive item such as very low current needs of an LED.

If that is the case, you could try separating wires in the harness.
Adding a big ferrite around the white wire (a few turns through it) might be enough to do it.

I suspect that you are spot on. The flash is really just a spit second and is certainly not the full illumination intensity of the indicator light. It is only noticeable during nighttime driving which I've been doing more of. I did a bit of wire cleanup behind the instrument cluster recently and loomed many of the wires for neatness sake; so proximity of the wires may indeed be the source of the issue.
Thanks!

 

[rkymtnflyfisher]

Voltage drop due to the inrush of the new load(s).


Ramp up your rpm and try it to see if it reduces the momentary blip.

 

[45Dougal]

I suspect that you are spot on. The flash is really just a spit second and is certainly not the full illumination intensity of the indicator light. It is only noticeable during nighttime driving which I've been doing more of. I did a bit of wire cleanup behind the instrument cluster recently and loomed many of the wires for neatness sake; so proximity of the wires may indeed be the source of the issue.
Thanks!

That's so often the way; you try to tidy something up, and you end up introducing a new feature.
You could try and unplug your headlight bulbs and check that it goes away - no bulb = no current surge.

 

[South Texas 97]

I have LED's in both my 97 series 80 and the FJ40 cluster. I have noticed they are very sensitive to voltage fluctuations, it could be an induction as mentioned above, or it could be a very slight change in voltage as both the heater and high beams pull quite a bit of current especially when first turned on.

 

[peesalot]

Try working the hazard switch a few times make sure its switching fully,