Many moons ago I ran into an issue with the fire dept. Having been in the fire service for about 40 years now,
I have a first hand been there done that with them. What I found was that on a number of the trucks, when
the original salesman demoed or trained the dept on use of the truck, he instilled a very bad habit on the boys.
What he did was to show them that when you go to start the truck, put the battery switch in the BOTH
position. More on this later. Then he instructed them to push both of the start buttons at the same time.
No matter how much you try and instruct the drivers, they still refuse to change. Their comment is, "This
is what the salesman showed us, it has to be the right way".
First of all, yup the truck has two complete starter motor systems. So when they mash both of the start
buttons on the dash, both starter motors will kick in. I try and tell the drivers that this is not a good
practice to be doing. The electrical system was not built for both starters to be cranking the engine
over at the same time. Second, the starters could cause a mechanical issue between them. The truck was
designed with 2 starters, so if one failed, you had another to be able to crank the truck over with. Most
departments that have trucks with the dual starters will put a sign on the dash to indicate which starter was
used last and flip the sign when they start the truck. This way both starters are used on a regular basis
and they get equal wear. One will not sit idle and not work when you really need it.
As for the battery switch in the dual position, this can be dangerous. When the truck batteries are new,
this is not a problem. As time ages the batteries, the storage capacity of the batteries will change. One
battery will always end up with a lower resistance than the other. The battery with the higher resistance
will not have the same capacity. It will not deliver the same high current output as the other. So when you
put the battery selector switch into the dual mode, you cause the dual battery system to seek it's own
voltage level. If one battery is way down, you stand the chance of the high inrush current to cause
damage to the battery that has the low voltage. If you do enough damage, you could also cause the
battery to short out and explode.
I am not saying that this is the case with your trucks, but I would look at the vehicle DC voltage while the
truck is being started and what it does as the engine starts up. If the voltage is low, trying to bring the
batteries back up to a normal voltage, the radio might not like it.
On another note, Motorola doesn't like to admit to it, but they had a big problem when they first came out
with the 05 heads. A number of agencies had the same problem that you are describing. The solution was
to send the original heads back and they were replaced with a new version that corrected the problem.
Not being one that gets to see all the service notes that come out, I am not sure this was ever let out of
the closet.
If you go over your trucks carefully and don't find any voltage issues, I would lean on the regional Motorola
manager and get his butt involved. He can make a few phone calls and make things happen. He will probably
ask what version level the heads have. I think it is both a software and hardware issue that caused the
problem I am talking about. The software (firmware) only upgrade didn't solve the problem.
Jim
Jim
nickburns186 wrote:Thanks for the advice Jim. Yes, they are the O5 (didnt know the 2500's came with any other head). They are installed in fire trucks with the ignition sense wired to the master battery switch. I wholeheartedly agree with all the items you listed, I just can't get past the fact that out of 30 or so radio's, only the remote mounts are exhibiting this behavior. Motorola doesnt seem to know what the issue is either. Their first step was to send new firmware which didnt fix the issue. We are going to check and double check the wiring tomorrow and then go from there. Thanks again.