I have a 2004 MDX, The issue is with the radio/navigation/blower control unit at various thmes the entire unit cuts out when you hit the brake,use the turn signal. Has anyone had this problem or what to check for. Thanks for any help
Sounds a lot like a loose / intermittent connection. Troubleshooting something like this normally involves pulling it all apart and trying to replicate the symptom by wiggling things. If that doesn't work, you have to find a wiring diagram and get a meter and start trying to trace out the problem. But from your brief description, it could be almost anything, though I'd bet on an intermittent power connection.
You need a shop manual w/ wiring diagrams to guide work. It could be a simple loose ground G401, intermittent power supply, etc. Access to unit also requires special knowledge from shop manual. check automanualsource.com for inexpensive download manual.