-
Hey Guest!
British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!**Upgrade Now**
(PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Hey - did you know if you click on the title of a thread it will take you to the first unread post since you last visited that thread?
but were afraid to ask: 
STOP!! Never post your email address in open forums. Bots can "harvest" your email! If you must share your email use a Private Message or use the 
smilie in place of the real @
Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
TR6 Blower fuse
- Thread starter davjac889
- Start date
Share this page
Offline
Sounds like it could be poor grounds - check all your ground connections, Bill.
TR3driver
Great Pumpkin - R.I.P
Offline
I don't think it's grounds. The heat means that there is an excessive voltage drop at the fuse block.
First question, what are you using for a fuse? Lucas repro or AGC?
Assuming you have either the proper Lucas "35 amp" or an AGC 20, then the problem has to be a poor connection at the fuse block. I'd start by polishing up the surfaces of the tabs that grip the fuse, with a Scotchbrite or similar, as well as the mating surfaces on the fuse. If that doesn't solve the problem, then you'll need to do some checking with a voltmeter or DMM, right at the fuse block, with the heater blower running. You should have no more than about 0.1 volts from the white wire (which is power in from the ignition switch) to the green wire (power out to the heater, turn signals, etc.)
I forget offhand how the TR6 fuse block is constructed; but on a Stag fuse block, there are copper rivets that are supposed to carry the current between the fuse clips and the wire terminals. Over time, the plastic shrinks until the rivets are no longer tight, and then the copper corrodes to provide a high resistance connection.
FWIW, I once had a similar problem with the (aftermarket) headlight fuses on my TR3A. Couldn't see any corrosion, but the tabs were not making good contact with the fuse even after replacing the fuse. The heat literally melted the solder inside the fuse! Which led to a fuse that was visibly fine, but would not carry current (the broken joint was hidden inside the end cap). Few seconds work with a Scotchbrite and the problem never came back again.
First question, what are you using for a fuse? Lucas repro or AGC?
Assuming you have either the proper Lucas "35 amp" or an AGC 20, then the problem has to be a poor connection at the fuse block. I'd start by polishing up the surfaces of the tabs that grip the fuse, with a Scotchbrite or similar, as well as the mating surfaces on the fuse. If that doesn't solve the problem, then you'll need to do some checking with a voltmeter or DMM, right at the fuse block, with the heater blower running. You should have no more than about 0.1 volts from the white wire (which is power in from the ignition switch) to the green wire (power out to the heater, turn signals, etc.)
I forget offhand how the TR6 fuse block is constructed; but on a Stag fuse block, there are copper rivets that are supposed to carry the current between the fuse clips and the wire terminals. Over time, the plastic shrinks until the rivets are no longer tight, and then the copper corrodes to provide a high resistance connection.
FWIW, I once had a similar problem with the (aftermarket) headlight fuses on my TR3A. Couldn't see any corrosion, but the tabs were not making good contact with the fuse even after replacing the fuse. The heat literally melted the solder inside the fuse! Which led to a fuse that was visibly fine, but would not carry current (the broken joint was hidden inside the end cap). Few seconds work with a Scotchbrite and the problem never came back again.