Truck Won't Start - Batteries/Alternator Are Good

**jgruberman** · 08-25-2022

Originally Posted by Greenebelly

I work with batteries every day.

Your “new” battery will only be as good as your old battery as soon as you hook it up.

It’s unfortunate, but both must be replaced simultaneously if you want a new performance.

Unfortunately, I will have to wait for at least a few weeks due to financial strain.

Is it worth keeping the "Still OK" one around in case of unforeseen issues?

Or should I try to get them to swap it for a warranty?

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**Greenebelly** · 08-25-2022

Absolutely.

Keep it off of the concrete floor and put on a trickle charger.

It never hurts to have a backup.

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**Corkey** · 08-25-2022

I hate haggling with warranty issues, as they fight with you every step of the way.

You paid for it, now get what you can from them.

They should know that if one battery is bad, they run in parallel; your good one will follow sooner than later.

Squeeze the rock hard enough it'll break sooner or later.

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**jgruberman** · 08-25-2022

Originally Posted by AK Bob

Yes, let see what readings you get back probing each sensor wire on volts DC. You will need the key in the run position and wheels stationary.

I got under the truck, traced the speed sensor wires back along the frame to where they connected and admittedly, have no idea what to do with the multimeter. I am quite versatile in many things, but not when it comes to using a multimeter and testing things. I don't even see anywhere to easily reach a probe in behind the plug and wire connection...

I believe these are the connections.

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**AK Bob** · 08-25-2022

Originally Posted by jgruberman

I got under the truck, traced the speed sensor wires back along the frame to where they connected and admittedly, have no idea what to do with the multimeter. I am quite versatile in many things, but not when it comes to using a multimeter and testing things. I don't even see anywhere to easily reach a probe in behind the plug and wire connection...

I believe these are the connections.
https://uploads.tapatalk-cdn.com/202...277cf7abdd.jpg

Yes, I understand it can be very difficult to even get to some of these connectors and some are hard to back probe. As I was reading on Mitchell last night I can understand why they want you to use a scanner capable of reading the ABS module for codes (see post #30). Hard to tell from the photo but is there any way you can back probe the wires? If not then at least disconnect each one and check the harness side for the 5V reference. Just finding the connectors and unplugging them to check for corrosion or damage may find an issue.

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**Corkey** · 08-25-2022

If it's all in 1 loom of things, it may be the only way without cutting into the wires to separate is to unplug the connecter and ohm it out?

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**jgruberman** · 08-25-2022

Originally Posted by AK Bob

Yes, I understand it can be very difficult to even get to some of these connectors and some are hard to back probe. As I was reading on Mitchell last night I can understand why they want you to use a scanner capable of reading the ABS module for codes (see post #30). Hard to tell from the photo but is there any way you can back probe the wires? If not then at least disconnect each one and check the harness side for the 5V reference. Just finding the connectors and unplugging them to check for corrosion or damage may find an issue.

It's a bit difficult to get in there, but I can shove a probe tip into there... and put the other side on the chassis?

Will EACH wire on EACH harness have 5v? Or will only one of those wires have 5v and the other is the ground?

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**AK Bob** · 08-25-2022

Originally Posted by jgruberman

It's a bit difficult to get in there, but I can shove a probe tip into there... and put the other side on the chassis?

Will EACH wire on EACH harness have 5v? Or will only one of those wires have 5v and the other is the ground?

Measuring each wire to ground with the harness plugged in I would expect to see close to 5V on the plus wire and something less on the negative.

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**AK Bob** · 08-25-2022

Originally Posted by Corkey

If it's all in 1 loom of things, it may be the only way without cutting into the wires to separate is to unplug the connecter and ohm it out?

On some late model vehicles (such as Jeep, Chrysler and others), a different type of wheel speed sensor is used. Active wheel speed sensors (also called Magnetic Resistance Element or MRE sensors) use a Hall effect sensor to generate a digital speed signal with a square wave pattern. This type of sensor can generate a more accurate wheel speed signal at low speeds (down to 1 mph) than a magnetic WSS. It can also tell if the wheel is rotating forwards of backwards.

NOTE: Active wheel speed sensors cannot be accurately tested by measuring resistance across the sensor's terminals. You have to look for a good return signal from the sensor while it is receiving power from the control module or a 12-volt battery, and while the wheel is turning.

If you have a scan tool that can read ABS codes (not just engine/transmission codes), you can also check for wheel speed sensor codes on your vehicle. A scan tool that can also display the speed readings from each sensor while driving can also help you pinpoint which sensor is bad. All the sensors should read the same while driving straight ahead. If one is showing a different speed (faster or slower than the others), there is a problem in that sensor circuit (either a bad sensor, a faulty magnetic sensor ring, or a wiring fault). The sensor may be misreading wheel speed if the magnetic ring on the wheel bearing is cracked or damaged.

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**jgruberman** · 08-25-2022

Originally Posted by AK Bob

On some late model vehicles (such as Jeep, Chrysler and others), a different type of wheel speed sensor is used. Active wheel speed sensors (also called Magnetic Resistance Element or MRE sensors) use a Hall effect sensor to generate a digital speed signal with a square wave pattern. This type of sensor can generate a more accurate wheel speed signal at low speeds (down to 1 mph) than a magnetic WSS. It can also tell if the wheel is rotating forwards of backwards.

NOTE: Active wheel speed sensors cannot be accurately tested by measuring resistance across the sensor's terminals. You have to look for a good return signal from the sensor while it is receiving power from the control module or a 12-volt battery, and while the wheel is turning.

If you have a scan tool that can read ABS codes (not just engine/transmission codes), you can also check for wheel speed sensor codes on your vehicle. A scan tool that can also display the speed readings from each sensor while driving can also help you pinpoint which sensor is bad. All the sensors should read the same while driving straight ahead. If one is showing a different speed (faster or slower than the others), there is a problem in that sensor circuit (either a bad sensor, a faulty magnetic sensor ring, or a wiring fault). The sensor may be misreading wheel speed if the magnetic ring on the wheel bearing is cracked or damaged.

Is there a way to determine which sensor I have?

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