Fault in control circuit for primary emergency lights

[JPINFV]

So my company just uncovered a major problem with one of the ambulances. The ambulance is a 2007 Chevrolet Wheeled Coach Crusader with 22000 miles. The issue we recently found was that when the "primary" emergency lights are active the lights will shut off after around 30 to 60 seconds and restart again after around 30 seconds repeating ad infinitum. This occurs whether or not the light bar is active (tested both with and without the light bar) and the light bar didn't appear to affect how long it takes for the lights to shut down. During the shut down period, I haven't been able to find a way to restart the lights (toggling, for example, doesn't work). Unfortunately, there isn't a volt or amp meter built into the system. The "secondary" emergency lights work fine with or without the light bar.

Has anyone else experienced a similar issue with Wheeled Coach ambulances?

[Chief1C]

Have your main circuit board checked, soon. Ours began to burn solid, no flashing; then the siren went haywire, then the backup alarm came on.. Driving down the road, forward. Pulled over, and the siren went to a steady pitch.. and finally the mod filled with smoke. Tried to shut it off, no go, we had the key out.. and it still wouldn't turn off. The computer system took control of everything, had to disconnect the batteries and call for a flatbed. The main circuit board caught fire and was damaged through some sort of electrical fault. The electronic amp/volt meter wasn't reading, it just had the screen filled with Astrix symbols. Burned out the siren speaker and it's control box, Code 3 Siren equipment. No idea what the cause was..

Edited May 31, 2009 by 4c6

[island emt]

Wheeled Roach is famoous for their electrical system gremlins.

Could be a circuit breaker or relay or it could be just the junk quality of their electrical control systems.

[Arctickat]

Yup. replace the circuit breaker first, then go for the relay. If it continues check with an automotive wiring technician who would be able to determine what amp load the wiring can take without burning up, then increase the circuit breaker amperage.

Silly question....isn't this vehicle still under warranty?

[JPINFV]

I think it is, but not 100% sure. The vehicle is going in for service later this week anyways, so we're just adding it to the list of things to get taken care of.

[zippyRN]

has someone had to jump or boost start the vehicle at any time ? and did they do so counter to the instructions provided by wheeled coach ?

just some of the vehicles in Use by SJA here in rightpondia have a to have a pair of fuses pulled to isolate the emergency warning devices and body electrics and their computer controlled 'brain' before jump starting because you can fry the brain if you don't

[JPINFV]

I haven't heard any stories about jumping it and I'm sure I would have if it happened (advantage of working for a small company). Hopefully if anyone did jump it they'd turn off the battery switch...

[Dale]

Our happened, no patient on board, while just normal driving. Who knows, internal computer probably, allowed a surge or power or an overload.

For a vehicle that is only two years old and with that little mileage, make sure you let the seller know you want it taken care of under WARRANTY. Of course, that is the curse of some ambulance builders who try to use "all ecompassing" circuit board systems for the ambulance wiring. No one locally can troubleshoot or repair the problem.

And you have no volt or ammeter? Gee, they must have sold you one of those "low bid" spec rigs where it is not required by Federal purchasing specifications. Manufacturers will install whatever you request but you must pay for it in some cases.

[Dustdevil]

Wheeled Roach is famoous for their electrical system gremlins.

Definitely. And this exact problem in particular. I've experienced it with many Wheeled Coaches. I've had screaming fights with county commissioners over not buying anymore Wheeled Coaches because of this kind of thing. I don't know what the problem is, but they do manage to fix it pretty quickly.

[joesph]

Over heated relays possibly the relays may be good but they may need vented.