Club 80-90 Forums

Help please, I keep blowing and half melting a 8 amp fuse, which runs the heater / blower, this is a real hotch podge tangle of wiring and its very difficult to find wires and find out what they all do.
I wish I could rip it all out and start again but I can't.
Should I just put a bigger fuse in and hope for the best?

I think it should be a 20amp fuse for the blower. Haven't got a diagram in front of me only toilet paper so can't be certain.

lefty67 wrote:I think it should be a 20amp fuse for the blower. Haven't got a diagram in front of me only toilet paper so can't be certain.

And also replace those plastic bullet fuses with ceramic ones, so they cannot melt.

When this happened to me it was the blower motor.I hope that's not the case with you as it's a dash out job.

fuse no 10 16 amp for the blower and wipers on my van- 1983 DG according to the handbook.
David

Mine too, blower motor was seized and drawing big amps.
Replaced the motor but the damage was already done to the fuse box so it melts plastic fuses.
I avoid using the motor on full blast.

If a 16amp fuse blows when blower is running, the only way forward is to replace blower. If its an original blower motor it will now be drawing considerably more amps on startup than when it was new. Unfortunately most original blowers have already reached the end of their lives, or are about to. Sticking in bigger fuses might make the motor go, but the risk of a dash fire is much greater. If you dig around you'll find (in WIKI) a how to on removing dash as well as my PWM blower control upgrade.

You should also remove wiper supply from present fuse, and provide an independent fuse. (also in WIKI)

Ralf85 wrote:And also replace those plastic bullet fuses with ceramic ones, so they cannot melt.

Ceramic fuses are surprisingly hard to find these days. But the plastic fuses ought to be able to handle their rated current without melting, and should blow by breaking the metal link when the current rating is exceeded, rather than by melting.

So it's possible that the heat that's causing the fuse to melt is actually coming from a less-than-perfect connection between the wire and the fuse. If some of the strands in the wire have broken at the crimp, or the spade connector is a bit loose or corroded, then the connector may not be able to carry the required current comfortably and will heat up. I had exactly this problem, and the heat had caused the cable sheath to go brittle over several inches from the fusebox. I replaced the entire cable in the end.

Another thing to point out is that in pre-85 vans this fuse also supplies the wiper motor - lose one and you lose both. A crazy idea given that if it's wet outside there's a good chance your clothes will be damp and you're more likely to need the blower motor. Somebody obviously decided at some point that it was a good idea to put two high current devices, that are often likely to be needed at the same time, on the same fuse. There's an article in the wiki on how to separate these two items onto different fuses.

I purchased a circuit breaker bladed fuse for the blower motor, just to be on the safe side.

Sent from my F3111 using Tapatalk

I bought ceramic bullet fuses online. Also, try and get copper ones instead of the original aluminium ones, which cause corrosion and resistance build up with the copper connectors.

My Merc has got copper ones (tinned) but they still get crusty at the contact point. No moisture where they are situated to cause corrosion other than the sea air which I can't get away from.