I have a 2006 motorhome with the E450 chassis. It keeps blowing the 10 amp fuse in the Power Distribution Box (fuse #27). I have search online for the causes and have check a number of things. I rent the RV, so I do not know exactly when the fuse blows. I have check the engine battery and it is fine. The first time the fuse was blown, the RV was return and the coach battery was low. It was charged and that is when I figured out the what the p1633 code meant and replaced the first blown fuse. I started it and drove it a short distance and everything was fine. But, even with the blown fuse the engine runs great. When it was return the next time, I was told the the engine light come on in about 15 minutes of driving. The coach battery was again low and I find out that was not holding a full charge, so I replaced the coach battery and the fuse again. I though maybe the low voltage in the coach battery cause the low voltage issue when the RV was running and blew the fuse. I started it and drove it again and no engine light. When it was returned again, I was told the the engine light come on in about 1 hour of driving. I again replaced the fuse and I can not get it to blow. I checked the battery connections, volts of the battery (12.54 volts), with engine running (14.21 volts), I have checked for bad connections and bad wires. I have clicked on and off the a/c and everything works perfect. There are no modifications to the RV except for the radio, which has been in it for 5 years.

What else can I check? It is not thowing any other codes. Is it a bad PCM? Any help would be greatly appreciated. Thanks

 

Hello finerhomes and welcome to FTE.

P1633 means the voltage is dropping too low. Since you keep blowing a fuse, that would make sense. You have a short circuit somewhere in your wiring, or something being fed off of the Power Distribution Box is drawing way too much current. Take out fuse #27 and the problem will stop, a temporary fix at best.

Find out what is drawing to much current and repair it.

 

Fuse #27 in the Power Distribution Box (not the fuse panel) is the 10 amp fuse that goes to the PCM. From my understanding it is the Keep Alive Power to the PCM. Removing the fuse or leaving the blown fuse in, results in the engine light being on and a p1633 code.

 

Moved to the correct forum.