18049: Service Update – Intermittent Loss of Tail Lamps – 2018 Cadillac XTS

#18049: Service Update – Intermittent Loss of Tail Lamps – (Feb 26, 2018)

Subject: 18049 — Intermittent Loss of Tail Lamps
Models: 2018 Cadillac XTS

Reference Number: N172131740 Release Date: February 2018
Revision: 00
Attention: This service update includes vehicles in dealer inventory and customer vehicles that return to the dealership for any reason. This bulletin will expire at the end of the involved vehicle’s New Vehicle Limited Warranty period.
Make Model Model Year RPO Description
From To
Cadillac XTS 2018 2018

Involved vehicles are marked “open” on the Investigate Vehicle History screen in GM Global Warranty Management system. This site should always be checked to confirm vehicle involvement prior to beginning any required inspections and/or repairs.

Condition Certain 2018 model year Cadillac XTS vehicles may have a multi-use relay assembly that is not full seated in the underhood buss electrical center. This can cause an intermittent loss of tail lamps.
Correction Dealers are to remove, inspect, and if necessary, replace the multi-use relay assembly (tail lamp/park lamp).


Parts Information

Quantity Part Name Part No.
1 (As Req.) Multi-Use Relay Assembly (Tail Lamp/Park Lamp) 19116962

Reminder: Parts may be removed from Retail Inventory Management (RIM). Dealers should review the affected parts to confirm RIM managed status.Parts may have quantity limiters in effect.


Warranty Information

Labor Operation Description Labor Time Trans. Type Net Item
9103658 Remove and Inspect Micro Relay 11 (Tail Lamp/Park Lamp)

(Includes Replacement)

0.2 ZFAT N/A


Service Procedure

  1. Open the hood.

front compartment fuse block

  1. Locate the front compartment fuse block.
  2. Remove the fuse block cover.

Micro Relay 11

  1. Remove and inspect Micro Relay 11 for signs of arcing or damage (Tail Lamp/Park Lamp).
  2. Reinstall (or replace if necessary) Micro Relay 11.
  3. Perform a visual inspection of the fuse block to ensure all other relays are completely seated.
  4. Reinstall the fuse block cover and close the hood.


Dealer Responsibility

Whenever a vehicle subject to this service update enters your vehicle inventory, or is in your facility for service in the future, and the vehicle is still covered under the New Vehicle Limited Warranty, you must take the steps necessary to be sure the service update correction has been made before selling or releasing the vehicle.

All new, used, GM Certified Used, courtesy transportation vehicles, dealer shuttle vehicles, etc. in dealers’ possession and subject to this bulletin must be held and inspected/repaired per the service procedure of this bulletin before customers take possession of these vehicles. Involved vehicles must be held and not delivered to customers, dealer-traded, released to auction, used for demonstration, or any other purpose.

All GM Certified Used vehicles currently in the dealers’ inventory within the Certified Pre-Owned Inventory System (CPOIS) will be de-certified and must be held and remedied per the service procedure in this bulletin. Upon submitting an accepted/paid warranty transaction in the Global Warranty Management (GWM) system, the vehicle can be re-certified for sale within the CPOIS system, or once again be used in the CTP program.


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