Radio ! fuse blows all the time

Anonymous · March 10, 2011, 17:01

Hi all
Needs some help, went to use the car one morning and radio did not light up. checked fuses and radio 1 is blowing, disconnected all wire back to main wiring loom and still blows as soon as new fuse is put in. I assume this means between the fuse box in foot well and the end of the wiring loom for the radio there must be a short.
Any one has this prob and any ideas how to test this before i have to take all the wiring loom out as this doesnt look that easy

Cheers
Jon

aaronjb · March 10, 2011, 17:24

Is yours a UK car? There was a recall for the radio wiring loom causing shorts/fires/problems, Toyota might still undertake the fix (which, IIRC, was double insulating the wires around the stereo cage area)

Anonymous · March 10, 2011, 17:36

yea UK model, called them up and they said it had already been done. Really do not fancy taking all the loom out but want a head unit working

Anonymous · March 10, 2011, 19:13

was thinking of taking the continous live feed from the cig lighter and cutting the harness live wire, any one see any probs with this??

Anonymous · March 10, 2011, 19:35

you need to put a power probe on the live wire to the unit and see if it tells you its an earth if nothing ie fuse out then those wires are not the prob. might be something else on that fuse. if u put a hard live to it could cause more probs best to find where the break is.

richard

Anonymous · March 10, 2011, 20:30

i was thinking with fuse out, if i place a meter across the live and back to fuse and test the resistance if wire is intact then will get low reading if i dot he same between live and ground with fuse out i should get no reading if i do then ill know the live is shorting out, in which case need to take all the wiring loom out, so could i not just take the live from the cigarette lighter and just not put i fuse back in radio socket making that part of the wiring loom defunct. I dnt think the radio fuse feeds anything else. any one know if it does?

Anonymous · March 10, 2011, 20:42

if your using meter there is a bit on it where it will bleep if the two points on the meter touch. put on end of the meter on a live and the other to the body for earth. still think you need to find the prob coz it could cause a fire

Anonymous · March 10, 2011, 20:53

yea thats what i was going to do but just using the resistnace feature on the meter. Other option would be to use both the live and ground from the lighter and then not sue any of the old radio wiring, with no fuse in there there would be no current so would imagine should be safe and no risk of fire.

cclarke99 · March 10, 2011, 21:47

The radio fuse only powers the radio, so if you leave it out and use an alternative power source (e.g cigarette lighter) then there won't be any problems. The only difficulty is that if the loom is chafed or damaged, then it may get worse. I'd certainly try to find the fault, especially as it may be caused by some previous overheating of the wires in the loom . Follow the previous suggestion to check from the radio supply to earth and try moving or bending the loom to see if you can locate the fault. If you can then you may be able to unwrap that part of the lom and find the damage.

Anonymous · March 11, 2011, 18:54

so placed a meter on live and earth with fuse out and get a reading indication the live is shorting out somewhere, tried moving loom to see if can find fault but no luck. So suppose only option is to unwrap it all and look for the fault Great

cclarke99 · March 11, 2011, 20:02

Try disconnecting the earth points at the top of the left and right hand instrument panel braces. If this clears the short, then the fault is at the radio end of the loom. Also try the earth point inside the sill by the fusebox. What resistance does the meter read?

Anonymous · March 11, 2011, 21:29

At the moment im connecting the meter to the live of the radio wiring loom and the negative, so if i remove the grounds as you descibe i do not see how that will show where the fault it as the ground and live would still be touching only thing i can think is to attach the ground to the battery then by removing the grounds it would indicate if it is a ground wire that is being touched and which one it is, if it doesnt solve it suppose it would mean that it could be the live touching the chassis some where

cclarke99 · March 11, 2011, 23:11

Don't forget, though, that the negative wire from the radio is grounded at the earth point I described (the right hand one). So if the live wire is shorted elsewhere to earth, current from your meter will flow through live wire, through the short to the body, through the body to the earth point and back to your negative connection. In fact disconnecting the earth will tell you if the short is directly to the radio negative wire (it will still be there even after you've disconencted the earth) or elsewhere in the loom. If it's to the negative wire then you won't have to unwrap much of the loom to find it

Anonymous · March 12, 2011, 12:19

Thanks for your help so far cclarke. Ok so removed earth point and still had the short present. tested the live from the fuse box to the radio and the wire is sound and not broken any where. but when ever i place a meter on the live of the radio and against any metal parts under the glove box i get a reading. This therefore mumst mean the live wire is touching some metal body work shorely, or a negative wire in the loom. i have unwrapped alot of it but unable to see whre the problem is, i can not get to the loom under the glove box and air bag. I noted the 2 wire blue with grey leave the fuse box, any one know where the other one goes?? Starting to think its more hassel than its worth and maybe bodge it for time being and get rid of the car.

cclarke99 · March 12, 2011, 13:55

Following your comment on the two wires in the fusebox, I've just discovered that the radio 1 fuse also supplies the aerial motor. Sorry I didn't point this out to start with but this part of the picture is not clear in the information I have. Trying to locate the problem in the wire going all the way to the back of the car is a mammoth task, so I probably not worth it. There is a connector inside the kick panel on the drivers side (there are three, grey, orange and white, the one you want is the white one) try disconnecting that, also disconnect the power from the relay (under the plastic cover on the drivers side in the compartment behind the seats to make sure the problem isn't there. Once again, sorry for wasting your time with the previous advice.

Anonymous · March 12, 2011, 16:56

Sorted the issue with the radio, i took a chance and cut one of the wires coming out the fuse box. This ended up being the wire that goes to the electric ariel, now the short is gone so the radio is fine.
Still get a radio reception so thinking of leaving it at that. However any one know how to take the ariel out so that i can see if its a problem there, or where this wire goes to so that i can check each junction. thanks

cclarke99 · March 12, 2011, 18:53

The wire goes across the dash down through a connector inside the RH kick panel to the aerial relay (see post above for details) From the relay power goes to the aerial.