radio, interior dome not working

Hi All,

I had an after market radio in my 99 Dodge Ram 1500 (installed when I purchased the truck).  A short time after buying the truck the radio began working intermittently.  One time it would work properly, next time only the front or rear speakers would work, next time it powered up but no sound at all.  As such, I believed that it was a fault with the radio and went out and purchased a high end Kenwood which was fitted by the shop I purchased it from.  At the time I was told (and charged) for a new wiring harness for the redio.  This radio was installed about 3 months ago and has not been used a great deal during that time - driving my Vette is more fun than the Dodge :).  Anyway, two weeks ago the new radio started doing the same thing as the previous one - would work one day and not the next.  Last week, I turned the radio on (hoping it would work) as soon as I did both the radio AND interior Dome light stopped working.  Now I have no radio or interior lights.

I was of the impression that there was no connection between the interio lights and the radio, if I am correct then both the radio and interior lights suddenly stop working is pure coincidence.  If not could someone tell me where I should start looking for the problem?  I am not overly concerned by the radio not working but not having interior lights when I open the doors is very frustrating.  Is there a connection between the two? Would an option be to remove and refit the radio to see if that has an impact? Could it be the switch thing that controls when the interior lights come on? If so, how do I change that and what is involved in changing it?

Any advice (other than sell the truck) would be appreciated :)

Cheers,

Womabt457

The radio's constant power connection and the domelight probably share a fuse. 

check if there is a fuse labeled "IOD" ignition off draw

And I wonder if the fuse contacts (else other connectors) are overheating or failing though higher than intended current. I prefer direct audio-power runs direct from the battery- fused of coarse. And thru a relay if wanting ACC control of it.

Thanks to all for the replies - much appreciated. I am an idiot "...The radio's constant power connection and the domelight probably share a fuse..." Would that type of installation be normal for a "professionally installed" radio? I mean, would a professional wire the Radio into the interior lights, which I am assuming would have to happen if both the radio and dome lights share the same fuse? Ween "...check if there is a fuse labeled "IOD" ignition off draw..." I have checked all of the fuses located on the dvr's side of the dash and all seem okay. Likewise for those beneath the hood. Would the fuse you are talking about be located elsewhere, perhaps an in-line fuse some where? oldspark "...And I wonder if the fuse contacts (else other connectors) are overheating or failing though higher than intended current..." Is there a way that I can tell if that is happening? "...I prefer direct audio-power runs direct from the battery- fused of coarse. And thru a relay if wanting ACC control of it..." This might be the solution to the radio problem, and possibly correct the dome light issue as well if what has been suggested is correct. I really don't care if the radio comes on with the ACC or not, so that would not be an issue for me. In the event I take this option, am I correct is saying that all I have to do is locate the "Power wire" for the radio, disconnect that from where ever it is currently connected, then run that wire directly to the + terminal of the battery using an "in-line fuse"? Or, should I disconnect all of the current wiring (presumably from the ignition switch) and use a completely separate setup? Does that make sense at all? If that would be the best option, what would I need to do (parts etc) to achieve that aim? Thanks again to all who replied. Have learn't a few things already and all your answers have been helpful and thought provoking.Cheers,

Womabt457

A professionally installed radio would use the OEM radio's wiring. It is common for the OEM radio wire to share a fuse with the Dome, Cigarette lighter, Horn or some other device.

i am an idiot wrote: A professionally installed radio would use the OEM radio's wiring. It is common for the OEM radio wire to share a fuse with the Dome, Cigarette lighter, Horn or some other device.

Thanks I am an idiot (which, by the way, your not!) I will re-check all the fuses again and see what happens.Cheers,

Womabt457

wombat457 wrote: {OldFart: "And I wonder if the fuse contacts (else other connectors) are overheating or failing..."} Is there a way that I can tell if that is happening?

Feel for heat or warm spots. That indicates a high current & high resistance combination [proportional to R x I^2; ie - proportional to resistance, and proportional to current-squared = I x I; hence why a current increase can hasten onset of fire LOL! ] But BE CAREFUL! Fuses can be HOT, and so too a faulty connection or cable. And don't confuse "normal" heat - eg, a starter cable after excessive cranking; a fuse running abnormally around 100% rating due to short-term high loading. Or wiring heated by heater vents & engines! Or you can measure the load currents, else estimate. EG - dome light 10W => ~1A. If the radio is 10A (for say a 2x45W RMS output running at max, or 4x45W at half), then a 10A fuse & circuit may have troubles.    FYI - usually circuits should - on average - be run at no more than about 70% of rating. EG - a 10A fuse should "normally" carry no more than 7A - even though that can run at 10A & even 11A all day.      The problem is usually telling if a contact has been heat treated, though again, the heat test is surprisingly good - it's a vicious circle: contacts are heated and lose tension or conductivity (resistance increases) to heat increases, so more "damage" etc. [ FYI: I first noticed that on my car's headlight fuse - the 3AG old glass types. Intermittent loss of headlights (actually only once - 150kmh on full beams on a narrow winding mountain road) was traced to the 35A glass fuse's contacts which, during its 25-odd years, had lost their tension, and were DISCOLORED (another good sign - dark copper etc instead of bright & shiny). I have since seen the same problem with many connectors - especially tensioned ones (like spades & blades etc). ] And bad contact/s can simply be due to oxide & corrosion. Hence the common fault finding method - disconnect & reconnect all connectors; and fuses - though they should be rotated with same-sized fuses to see if the problem also rotates. Else clean all contacts.

wombat457 wrote: I really don't care if the radio comes on with the ACC or not, so that would not be an issue for me.

What can I say? Wombats are Australian; so am I? I do direct battery connections for my audio mainly to have a clean supply. (Usually both +12V & ground; and fused at the battery +12V end of course!) The ability of the OEM wiring has little to do with it - but would often be another reason in my cases!    Plus I want to be able to listen to music whilst waiting for help after locking myself out and leaving the with IGN or ACC off.

Thanks oldspark, although I didn't quite understand the technical equations, I did/do understand all else that you provided, and I thank you for the length and detail of your reply. Looks like I have some work to do over the forth coming days then - hope the temp goes above 25F so I can :) Wombats truly are Australian, just as I am - born and bred, raised, dragged up etc. But, I now reside in the US - marraige does funny things to a guy Not only do the "Yanks" (meant in the kindest way of course) drive on the wrong side of the road, they seem to do a few things a little differently than Aussie's, ie: rather than have a simple wiring system Red, Black White, they tend to like lots of colors which (for an auto electrical illiterate Aussie) does make things a little more confusing Cheers,

Womabt457

The equations are simple: V = IR (Ohms Law: voltage (drop) equals resistance R time the current I going thru it.) P = VI (whoever's law: power equals voltage times current) All units are Volts, Amps, Ohms, Watts. (Hence can be milli-Amps & kilo-Ohms etc.)    Combine those 2 formulas to get P = VV/R = IIR. (that's VxV/R & IxIxR) Congrats on your marriage. I still have to knock the yanks - especially now that I am an Aussie Citizen - however I like you know that yanks are amazingly helpful & tolerant to/of people. Aussies too can likewise be amazingly helpful & friendly, but when intolerant, it leaves something to be desired. (Only recently have I understood the extent of "tall poppy syndrome" in Oz.) But that's all on a personal level - not to be confused with politics and media limitations. I won't mention foreign policy. (We have "illegal" Refugees!!) I take it stateside lacks federal standards? That's the beauty of independence! Domestically (for AC) we have our National Standards. For everything else, we have the Japs.