Discussion
I suppose that should be wiper not wipers
Just before tucking it away for the the winter I accidentally operated the wiper, it did not return to its home position.
(I can't ever remember actually using them, probably why it is faulty.)
Is that a motor, switch or relay problem?
It's an 85 series 1.5 US model, am I correct in assuming those bits around the steering wheel are Triumph?

Just before tucking it away for the the winter I accidentally operated the wiper, it did not return to its home position.
(I can't ever remember actually using them, probably why it is faulty.)
Is that a motor, switch or relay problem?
It's an 85 series 1.5 US model, am I correct in assuming those bits around the steering wheel are Triumph?
If the main lights switch is on the side of the column, it's a Rover column (it'll be adjustable as well).
Otherwise (and more probably) it'll be ex-TR7.
There are a few possibilities (odds-on whatever I say will be wrong; this being a TVR you'll find a different fault, but here goes...)...
There isn't a relay to worry about. If you have an 'intermittent wipe' position on the stalk then there's a delay module, but that wouldn't (I don't think) affect the normal operation if it failed.
The park function is effectively built-in to the wiper motor (very like the switches in the motors that operate the headlamp pods). If that switch goes dicky, the motor stops wherever it fancies. It may sometimes park properly, which points towards an intermittent fault with the park switch.
The wiper arm is splined to a short spindle in the 'wheelbox' under the windscreen. The wheelbox is driven by a flexible cable from the wiper motor. A failed cable, stripped drive gear or stripped splines will all leave the wiper in limbo. Clue: you'll be able to manually swing the wiper back and forth with little resistance.
The carbon brushes within the motor could be worn to excess, or the copper commutator against which they bear could be dirty. This will stop the motor turning. Giving the motor a thump may temporarily restore operation, which is itself a clue.
One of the worst-case scenarios is that the wheelbox splindle has seized due to corrosion. If it does, the motor can do one of two things. It can strip the drive gear as mentioned above, in which case you'll be able to hear the motor whirring but the wiper won't move.
The other, more serious scenario, is that the motor is stalled by the seized mechanism. This causes current to keep flowing in the motor as long as the wiper switch is on... in fact it may even flow as long as the ignition is on, regardless of wiper swith position. This is bad because (a) it can fry the motor so that once you unjam it, it's knackered anyway or (b) it starts an electrical fire. If the motor's hot, that's a good sign that electrons are flowing when they shouldn't be.
You might think a stalled motor would blow the fuse but that's not necessarily the case as the motor's only rated at 16W (about 1.25 Amp) whereas the fuse could easily be 5A or even more if previously substituted incorrectly.
Otherwise (and more probably) it'll be ex-TR7.
There are a few possibilities (odds-on whatever I say will be wrong; this being a TVR you'll find a different fault, but here goes...)...
There isn't a relay to worry about. If you have an 'intermittent wipe' position on the stalk then there's a delay module, but that wouldn't (I don't think) affect the normal operation if it failed.
The park function is effectively built-in to the wiper motor (very like the switches in the motors that operate the headlamp pods). If that switch goes dicky, the motor stops wherever it fancies. It may sometimes park properly, which points towards an intermittent fault with the park switch.
The wiper arm is splined to a short spindle in the 'wheelbox' under the windscreen. The wheelbox is driven by a flexible cable from the wiper motor. A failed cable, stripped drive gear or stripped splines will all leave the wiper in limbo. Clue: you'll be able to manually swing the wiper back and forth with little resistance.
The carbon brushes within the motor could be worn to excess, or the copper commutator against which they bear could be dirty. This will stop the motor turning. Giving the motor a thump may temporarily restore operation, which is itself a clue.
One of the worst-case scenarios is that the wheelbox splindle has seized due to corrosion. If it does, the motor can do one of two things. It can strip the drive gear as mentioned above, in which case you'll be able to hear the motor whirring but the wiper won't move.
The other, more serious scenario, is that the motor is stalled by the seized mechanism. This causes current to keep flowing in the motor as long as the wiper switch is on... in fact it may even flow as long as the ignition is on, regardless of wiper swith position. This is bad because (a) it can fry the motor so that once you unjam it, it's knackered anyway or (b) it starts an electrical fire. If the motor's hot, that's a good sign that electrons are flowing when they shouldn't be.
You might think a stalled motor would blow the fuse but that's not necessarily the case as the motor's only rated at 16W (about 1.25 Amp) whereas the fuse could easily be 5A or even more if previously substituted incorrectly.
Wedg1e said:
jeff m said:
Cheers all,
I'll get to this one day this week and post result.
Really glad nobody mentioned any sort of saw to be used for access
Er... if it turns out to be the wheelbox you'll need to take out the heater to get at it.I'll get to this one day this week and post result.
Really glad nobody mentioned any sort of saw to be used for access

Which means taking the dash out...

I just had a quick look....bu66er... they really hid that baby. The wiper does work and can be "homed" by re-operating it. As it never goes out in the wet I think it can remain a "to do" job for now

You only need a saw if the mechanism is totally locked up.
Most of the jobs can be done by removing the wiper motor assembly from the end of the mechanism tube. You will need the help of a contortionist for this though.
I did cut a hole in the bulkhead before realising this.
The first job is to remove the wiper arm from the wiper shaft, then it should be possible to unscrew the wiper motor from the mechanism outer tube and pull the motor and spiral wire out.
If the wipers work but don't self-park then the problem is either wiring or inside the motor wheel box, you shouldn't need to chop anything.
Info based on a late '85 390SE.
Russ
Most of the jobs can be done by removing the wiper motor assembly from the end of the mechanism tube. You will need the help of a contortionist for this though.
I did cut a hole in the bulkhead before realising this.
The first job is to remove the wiper arm from the wiper shaft, then it should be possible to unscrew the wiper motor from the mechanism outer tube and pull the motor and spiral wire out.
If the wipers work but don't self-park then the problem is either wiring or inside the motor wheel box, you shouldn't need to chop anything.
Info based on a late '85 390SE.
Russ
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