DRL only work when jumped 01 Yukon

[Dvdtactical]

Need DRL to "function as intended" to pass safety inspection. Fuses and relays seem to all be ok. DRL only come on when jumped at relay in under hood fuse box.

 

[Fless]

Likely the ambient light sensor on the dash. But put a capable scanner on it to see if that function is working correctly in live data.

For replacement, see the link below but use the links at the top of your browser to find the similar site for your vehicle, if that's not it.

Ambient Light Sensor: Service and Repair — 2001 GMC C 1500 Yukon 2WD V8-4.8L VIN V Service Manual | Operation CHARM

Detailed repair manual for the 2001 GMC C 1500 Yukon 2WD V8-4.8L VIN V.

charm.li

Same vehicle, electrical diagram:

W/O Snowplow Package — 2001 GMC C 1500 Yukon 2WD V8-4.8L VIN V Service Manual | Operation CHARM

Detailed repair manual for the 2001 GMC C 1500 Yukon 2WD V8-4.8L VIN V.

charm.li

 

[Dvdtactical]

Thanks for the diagrams. Headlights turn on and off when sensor is covered and uncovered. Will hard wire DRL to key on circuit to pass safety inspection.

 

[Fless]

FWIW the gear selector should not be in Park for the DRLs to be on.

 

[Doubeleive]

and no parking brake set, check the contact on parking brake

 

[Doubeleive]

if you need to verify and do not have a helper or reflective surface, you can chock the wheels, put it in reverse and get out and look.