issues

[YukonJ]

Hey all...new to the family . Just picked up an 01 Yukon XL with the impressive 8.1L running things nicely. It has 160k on it and I had all fluids and filters repalced when I bought it. I have a couple minor irritations that I can't seem to figure out. (Sorry if they've been discussed ad nauseum but I couldnt find anythign in search)

#1 the headlights come on when I start the truck...not EVERY time but mostly. When they arent on then I get the DRL's. I can cycle them on and off (Both HL and DRL) with the dome light switch X4 thing. Also, my dash light dimmer dial only goes on or off, no variation. Would replacing the HL switch assembly correct both of these issues?

#2 My idle at warm is around 500-600 on the dash and when sitting at stop light I get a slight pulsation and dip in RPM, not enough to kill engine. The front fuel pump went out on me yesterday so I just had that replaced. The mech said everything showed normal on the scanner (no codes thrown). He cleaned the TB but it's still doing it...what to do?

Other than that I LOVE the truck so far. Thanks for the help and I hope I can help some on here as well

-Jason

 

[YukonJ]

OK so 18 views but zero replies...do you all not like newcomers around here or did I post this question in the wrong section? lol. I figured surely SOMEONE would chime in.

 

[Rivieraracing]

There is a sensor at the top of your dash next to the windshield defroster that senses if it's dark enough outside for the regular headlights or light enough for the DRL's, so it controls the problem you have. You can turn the headlights on if you want with the switch but otherwise it's automatic!

So for your dash light dimmer switch, you dash lights will only turn on when the headlights are on, not the DRL's. So, are you trying to dim the dash lights when the headlights are on? Is that your question or are you trying to dim your interior lights (which you can't do with that switch if that is indeed what you are asking)

As for the pulsating idle, he may not have done a great job with the TB cleaning because that is often times the cause for the idle, but if your fuel pump went out recently and it idled well before, you could either be looking at a clogged fuel filter or a plugged injector, these are by the way internet guesses!! Keep us informed!!

 

[YukonJ]

Thank you for the reply Chris...I think I didnt make my point clearly...the headlights come on as soon as i turn the key, day or night...(with the headlight switch in the off position. (well NOT every time i turn it, but 99% of the time.) If it's the 1% and they dont come on then my DRL's work as designed, when lever is put into gear. I figured out today that if I just tap the "dome override" switch the headlights will go out. As for the dimmer switch, when the headlights at in the ON position I only get off or on of the dash lights, no dimming. All of this leads me to believe that my whole headlight control switch may be bad.

The idle issue was present before the fuel pump went out. When i bought the truck i had the fuel filter replaced and he cleaned the TB...it is marginally better now after a second cleaning so maybe I need to do it myself so I know it was done, lol. I also like your though process about an injector...is there a test for this?

Thanks again.

 

[Rivieraracing]

Thank you for the reply Chris...I think I didnt make my point clearly...the headlights come on as soon as i turn the key, day or night...(with the headlight switch in the off position. (well NOT every time i turn it, but 99% of the time.) If it's the 1% and they dont come on then my DRL's work as designed, when lever is put into gear. I figured out today that if I just tap the "dome override" switch the headlights will go out. As for the dimmer switch, when the headlights at in the ON position I only get off or on of the dash lights, no dimming. All of this leads me to believe that my whole headlight control switch may be bad.

The idle issue was present before the fuel pump went out. When i bought the truck i had the fuel filter replaced and he cleaned the TB...it is marginally better now after a second cleaning so maybe I need to do it myself so I know it was done, lol. I also like your though process about an injector...is there a test for this?

Thanks again.

Well, try aiming a bright flashlight at one of the sensors on the dash (I think there is 2 of them and can't remember off hand which one controls the lights) and see if that makes the DRL's turn on instead of the headlights, that way you know if the sensor is working!
As for the switch, you may be right, it may be messed up!! If you had someone around you that you could swap one with to see if that's the case, that would be cool, they are not that hard to swap out!
As for your idle, I'd cleaned the TB out very very very good yourself, get some Seafoam "Deep Creep" or some other TB cleaner and hose it out real well, I'd also seafoam your truck while you are at it, through the master brake cylinder hose, also wouldn't hurt to buy some MAF specific spray and clean out your MAF, just don't use any compressed air on the MAF just spray it all over with the spray and let it air dry!

 

[YukonJ]

Thanks Chris...I will try all that.

 

[Rivieraracing]

No problem, if you have any other questions, feel free to pm me and I will see what I can do to help!!