Phil Farmer wrote:
>
> Situation: Power on brown wire to 1st fuse of fuse box. 1980 MGB.
> Power to ignition relay when key is turned on. Had problem
> in past with loose connection at
> relay. Getting power through relay with no problem.
> Appear to have a short or bad ground in circuits with
> radiator fans and on green wire circuit
> coming off second fuse.
> Have power at wire coming from relay to fuse box at 2nd
> fuse, only if I pull fuse and wire to fans.
> Have to pull both fuse and wire to fan to kill both
> circuits.
>
> Circuit breaker / fuse to fans appears to be OK. Fans work OK when pulled
> from circuit and run directly from 12 volt power. Cleaned the ground on the
> fender by fuse box. When I did this both circuits started working. Thought
> I had it solved. Went for drive down road 10 miles total. No problems.
> Went on another drive everything (on those 2 circuits) died about 1/4 mile
> down road. Same symptoms as above. To get power at fuse box from relay,
> have to pull fan wire and fuse. Tried cleaning ground again. No luck.
If, with the ignition on, you only see 12v at the relay side (Brown/White?) of
the
second fuse when you pull the fuse and fan connection, then that indicates a
high-resistance problem back towards the relay. Check the voltage at the relay
output and input while the fault is evident to help track it down. My Haynes
shows
the power feed going from the relay to the fuse post, then from the same fuse
post to
the fan and coil. If the engine still runs OK when the fault is on, and the
coil
wire is piggy-backed on the feed from the relay but the feed to the fans is on
a
separate spade on the fuse post, then I would check the relay/coil connection
to the
fuse post.
PaulH.
|