What can cause the 15 amp “tel” fuse to blow while trying to start the car. Its not supposed have a circuit? When I put a 30 amp fuse in its place, it blew again.
Fuses blow when there is an overload in the circuit such as a short or malfunctioning device. Replacing a 15 Amp with a 30 Amp fuse may cause significant damage or an electrical fire.
You need to find out what that fuse relates to and find the culprit.
Don’t quite know what to say… DO NOT EVER, EVER, EVER increase the amperage of a FUSE to try and get a circuit to not blow!! And that goes for EVERYTHING electrical. House wiring, vehicle, WHATEVER! DO NOT put in a LARGER Fuse!!! You are extremely ‘lucky’ that you have some sort of dead short (a MAJOR SHORT) - that will probably blow ANY fuse that you could put into it… Otherwise - you would already have MELTED wires; and probably a vehicle FIRE and the Fire Dept.; and you wondering why the heck you were so dumb to do that…
Call Toyota (Parts Counter); and give them the vehicle VIN and Year etc.; and inquire as to the nature/purpose of the ‘tel’ circuit. If parts can’t tell you - ask to speak to the Service Dept.; and inquire as to what the ‘tel’ circuit is/controls; and how much to get it repaired. Since you already tried a 30 AMP (WHOA) fuse which blew; I don’t think you can repair it yourself. Since you put in a 30 AMP fuse… 30 AMPS runs a hell of a lot of stuff in your HOUSE… let alone some small wires in your vehicle!
PLUS - did you just recently purchase this vehicle?? A slight web search seems to indicate the ‘tel’ circuit - is for MAYDAY or a type of Telephone; and all circuit diagrams which I looked at - stated NO Circuit. At the same time that they also stated it takes a 7.5 amp fuse… which is 1/2 the rating of the fuse which had blown; and which you doubled. I believe the correct rating for this circuit - would be 7.5 amps. However - the Fuse Box Plastic Cover will list the correct amperage for each fuse. If it is 7.5 amps - do NOT put in a 15!
Do talk with Toyota; and see if you can get some idea of the circuit purpose and correct fuse. After you have a bit of an idea of the circuit which has a failure - you can determine if you are taking it to Toyota; or to an independent Repair shop. But don’t try and repair this yourself - unless you are going to READ UP on electrical; your a quick study; and you are going to actually find out WHERE your MAJOR SHORT exists - and then repair that SHORT! Since you HAVE a DIRECT short! Blowing a 30 amp fuse - is not small potatoes. The ‘load’ for the circuit is no longer in the circuit. It is just as if you placed a large steel wrench across your vehicle battery terminals - and either observed the wrench MELTING - or the Battery EXPLODING! You have to get this SHORT fixed.