Turn signal makes RPM fluctuate (1 Viewer)

[JBS227]

Hello to all. I am a long time lurker. Solved many problems with this forum. But this one is strange.

I have a 99 landcruiser.

If I use the turn signal the following happens at any speed:

-The RPM fluctuates (drops) 800 RPM with each blink and returns to normal after the blink
-The cruise will disengage with the first blink

If I am parked and use the turn signal with the brake pedal up:
-The transmission bypass switch will disengage the shift lever lock with every blink

I have tried to find what these systems have in common. The only thing I can find is a grounding block behind the driver's fuse panel. Which appears to be good. Its free of corrosion and grounds and all points.

Any ideas?

Thanks for reading and no idea is a bad idea.

 

[Spike555]

Battery or alternator are weak.
Have them both tested. My thinking is the battery is not fully charged and the extra load causes the alternator to put out more juice which increases the rpm.
I could be totally off base, but having them tested is free so that's where I'd start.

 

[JBS227]

Battery or alternator are weak.
Have them both tested. My thinking is the battery is not fully charged and the extra load causes the alternator to put out more juice which increases the rpm.
I could be totally off base, but having them tested is free so that's where I'd start.

I haven't looked at it from that angle. I'll have it tested tomorrow.

Thanks

 

[mattafact]

Corroded grounds? Not sure where you're from and if rust is an issue but that's where I would start.

 

[2001LC]

Whereas charging system and ground was my first though, as I read "disengage the shift lever lock" I'm thinking this could be something more. We've seen many strange reports of gremlins with weak charging issues, but first I've heard of this.

Any other issues like buzzer sound with E brake on? or anything strange?

 

[JBS227]

Corroded grounds? Not sure where you're from and if rust is an issue but that's where I would start.

I checked the common grounding block. But not any other. I'll try to get my eyes on other, too.

 

[nmatcek]

FWIW on my previous truck, (different make) my cruise control would disengage with blinker or high beams. It turned out to be a weak battery. Alternator was fine.

 

[Spike555]

When self diagnosing always remember to...

K-eep
I-t
S-imple
S-tupid

 

[Kapo84]

Do you have LED turn signals? I have a '99 Land Cruiser which was exhibiting some weird things tied to my turn signals. Once I pulled my LEDs and LED flasher relay out and went back to factory, things went back to normal.

Here is the thread link:

Bizarre Electrical issues w/ LED turn signals

Good Luck.

Nate

 

[JBS227]

I had the alternatir and battery checked. The shop said they were fine. I can't find any corrosion on any grounds.

I had LED turn signals installed but have already returned to stock. However, this started shortly after I returned to stock. Could they be connected? Or is it coincidental?

 

[Julian Stead]

I would double check that the correct lamps are installed and that they are seated correctly. Also disconnect the battery for 30 minutes and then let idle for 15 mins. Worth a shot.

 

[JBS227]

I'll try it