Draining Lifeline: SureTrack Real Fix

by Abagail Lucero

Real Fixes from Mitchell 1’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is available at no additional cost in our ProDemand product.

This fix illustrates the power of the SureTrack community to quickly help a fellow tech solve a tricky diagnosis. SureTrack community member, Brwhitus, had a 2017 Jeep Cherokee with a draining battery, roll into the shop. They posed the question to the community, and with the help of Ericsautomotive and others, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

Vehicle
2017 Jeep Grand Cherokee Laredo – 3.6L Eng VIN G Eng CD ERC

Title
Battery Draw

Complaint
New battery is not holding a charge and is draining rapidly

Diagnostic Steps Performed/Parts Replaced

Performed a battery draw test with a scope multimeter and it shows a draw of 1128 milliamps on the main battery while the secondary battery is connected. But when the secondary battery is disconnected, it shows no draw on the main battery. Vice versa is also true, shows no draw on the secondary battery when the main battery is either connected or disconnected. Both the main and secondary batteries test well separately.

Additional tests of pulling fuses one at a time with the scope connected or by pulling the main power to the power distribution block showed no change in the battery draw.

Disconnected the auxiliary battery’s positive feed and the draining stopped. The diagram shows the auxiliary and main battery should both tie straight to the power distribution box. However, there is some sort of battery isolator mounted on top of the motor cover, just behind the power distribution box. This seems to have a positive feed from the auxiliary battery and feeds out to the power distribution box with a small 2-wire connection from the main harness, which looks like an OEM part.

Cause
After much time spent tracking down the drain, I found the power control relay was faulty for the automatic stop/run. The auxiliary battery ties into this control relay before feeding the power distribution block.

Correction
Replaced the faulty power control relay and now there is no further battery draw.

SureTrack® adds to the power of ProDemand® with an exclusive combination of real-world knowledge and powerful diagnostic tools, all wrapped in an interactive community of professional technicians. Designed to help automotive shops increase accuracy and efficiency from diagnosis to completed repair, the industry’s most comprehensive repair information resource is just a few clicks away.

Want more? Here’s how you can get a free 14 day trial of ProDemand:

Not a ProDemand customer yet? GET STARTED NOW with a 14 day free trial of Mitchell 1 ProDemand auto repair information by clicking below. No obligation. No credit card. No risk. It's 100% FREE!

Previous:
Featured TSB: Corvette Power Down

About the Author

Abigail Lucero 

Abagail Lucero is the Product Marketing Manager for ProDemand. She joined the company in 2011 as a member of the SocialCRM shop marketing team and has served in many roles at Mitchell1, lastly as Security and Compliance Supervisor. Abagail holds a Bachelor of Science degree from California University of Pennsylvania.