It is quite easy to cause serious and expensive damage to a computer-controlled vehicle.
Please consult your owner’s manual because jumping vehicles has changed a lot in the last 20 years.
NEVER touch or remove the battery cables while the engine is running.
Battery Vapor is Explosive – Keep all sparks away from the Battery.
It is important to reduce voltage surges into the system and avoid sparks where possible.
- Refer to your Owner’s Manual.
Start with your owner’s manual and know where your jumper connections and your vehicle’s battery are located. Today’s vehicles make what used to be a simple process much more complicated; and while helping a stranded motorist may seem like a noble task, it is not worth doing potential damage to your own vehicle.
- Locate Jumper Connections.
Pictured here is a battery and cables off a 2004 vehicle, please note that the red and black cables are clearly defined and there are no other devices connected to the cables. It is easy to tell which is negative and which is positive and where to attach the jumper cables.
In figure 2 we now have a newer vehicle with a couple things attached to the cables, these are fuses and if they blow you can and will be stranded, which is a high price to pay for trying to help someone out.
In figure 3 we have a battery that is hard to determine which terminal is positive & negative.
Notice in figure 4 the screwdriver pointing at the + that is molded in the battery case
In figure 5 you are looking at a positive jumper post, the battery on this vehicle is not accessible and the jumping will be done at these points under the hood.
In figure 6 this is the negative jumper post. The battery may be in the trunk or under the floorboards of the interior, so this is where the owner’s manual comes in to help locate these posts in the engine compartment.
- Connect the Cables in the correct order.
You must have cables connected positive to positive and negative to negative. We have had customers blow the PCM Power Train Control Module (Engine Computer) by hooking up jumper cables incorrectly. It is still possible to do damage even if we hook them up correctly.
Here is the order of which the cables should be hooked up, and since it is important not to have cables touching each other during this process, having two people doing this is highly recommended.
Red Cable (positive) to battery post on the dead car 1st
Red Cable (positive) to battery post on the jumper car
Black Cable (negative) to battery post on the jumper car
Black Cable (Negative) to ground on the vehicle. This is not going to the battery. Look for a negative jumper post and if you cannot find one look for a good bare metal place that will not move when the engine is started.
In figure 7 you are looking at the 3 strut mounting bolts and they are usually a good place to hook to avoid a spark at the battery.
- Attempt to start the disabled vehicle.
Once the cables are hooked up, start the jumper car 1st and let it run for a few minutes and then try the dead vehicle. If the vehicle does not start, let it run for a few more minutes and try again. Please understand the battery may be at the point of no return and/or there may be another problem that is preventing the engine from starting. One of the things we see commonly is what we call green death. This green corrosion forms on electrical connections and can keep a vehicle from starting as it will not let enough amperage to flow to start the vehicle.
- Unhook the Cables in Reverse Order.
Unhook these cables in the exact reverse order once again not touching any of the cables together during the process.
Black Cable (negative) to ground on dead car.
Black Cable (negative) to battery post on the jumper car
Red Cable (positive) to battery post on the jumper car
Red Cable (positive) to battery post on the dead car
Important Information: Even if the vehicle successfully starts, call your Trusted Mechanic to have the car inspected and the starting and charging system tested. At the least, you may have a bad battery but there are usually underlying problems which caused the battery to fail. See our page on Starting and Charging systems for more detail about this system. Do not take the vehicle to a parts store and just have the battery tested. There is no substitution for a qualified Technician looking at the entire system since you could possibly ruin a new battery by putting it in a damaged charging system.
This Article was Written by Jammin J Auto Visit us at Jamminjauto.com or give us a call at (314) 423-3876