MG T-ABC

I`ve two 45W spot lights fitted to my TF1500 ( they were there on purchase of the car). I`ve two questions. When on, even with engine running, they show a maximum discharge on the ammeter. By implication I`ve a short in the circuit. Whist it blew a 25amp fuse the 35amp survived strangely. So questions are what would the two standard fuses normal to be found in the fuse box. Why would it blow a 25amp but not the 35amp. I find it strange. There is no other load in place.

jddevel wrote: ↑

Thu Feb 08, 2024 9:05 am

I`ve two 45W spot lights fitted to my TF1500 ( they were there on purchase of the car). I`ve two questions. When on, even with engine running, they show a maximum discharge on the ammeter. By implication I`ve a short in the circuit. Whist it blew a 25amp fuse the 35amp survived strangely. So questions are what would the two standard fuses normal to be found in the fuse box. Why would it blow a 25amp but not the 35amp. I find it strange. There is no other load in place.

The main reason why I have fused all the circuits separately is because the original two fuse arrangement is a potential fire risk. I just don't trust them. I would make it a priority to find the short circuit.

I agree Ray and inline fusing is happening at the moment . Finding shorts not the easiest of tasks without an insulation tester as I`m sure you are well aware. As there are two spots first will isolate and fuse each individually -that I think the quickest method.

Don't forget it might be a problem with your switch. I wouldn't be happy with a high amperage going through an old switch on a wooden dashboard with fabric covered wiring. That is why I have added relays to all my switched circuits.

BTW, normal relays can emit high voltage spikes that can damage sensitive electronics; in which case (should you have any electronics) I would suggest fitting relays with diode protection. These 'diode relays' are polarity sensitive so if your car is positive earth you will have to reverse the normal 85 and 86 terminal connections.

Noted Ray. Thankyou