TVR Griffith 500 - Wiper motor issues?

[Jacqo le Jaq]

I've owned and enjoyed this car for nearly 4 years now, but the most frustrating thing is the continual failure of the wipers. I had a reconditioned motor fitted as that was the diagnosis by a TVR Specialist. I have also replaced the park switch 3 times since this and it has sorted the problem, but this time with a new park switch, connector and loom the wipers refuse to budge although they worked for about 5 seconds after fitting the latest park switch.

I suspected this may have been mechanical rather than electrical, but the fuse did not blow and stripping the motor showed zero damage to the nylon gear. No burning smells or mechanical noises evident. I thoroughly cleaned out the original hard grease and applied a modern lithium grease before reassembly.

I checked for 12V across Connection 1 (Earth) to Connection 3 (2nd speed), Connection 5 (1st speed) and Connection 4 (Live) on the park switch, all OK.
There was 0V across Connection 1 (Earth) to Connection 2 (Park), which I think is correct.I bench tested the Park switch for continuity, all seemed OK (2 Ohms max)

Having confirmed there was 12V to all feeds I used some jumper wires to connect directly to the wiper motor connections Blue (Earth), Yellow (Slow) and Red (Fast) and the motor did not operate. Checked continuity and it was around 40 Ohms. I suspect the wiper motor, but I'm not experienced in auto electrics. I would be very grateful advice from anyone with more knowledge on these wiper motors before I try and get a replacement. I'm concerned about reconditioned motors if it turns out the previous one has failed as it seems fairly expensive.

I have a copy of the original Lucas wiper motor manual and having stripped the drive section down it appears identical to the Lucas 14W design used on Mini, Land Rover etc. I am aware the crank gear is set upo for 170 degrees on the TVR, so different from the Mini one. Also I believe the TVR motor was 29W. I am wondering if I could buy the Mini motor, rebuild with a 170 degree crank gear and fit the Motoclan motor upgrade. This will not be cheap and assumes I can source a new 170 degree crank wheel. I would get an expert to do this if I could find one.

Any suggestions would be be gratefully received, thank you

[Loubaruch]

In your search for the problem you have missed out three possibles:
The wiper/wash switch,the wiper delay relay and the wiring.
I would be investigating the wiper switch first check that voltage is leaving that in the various positions.

[Jacqo le Jaq]

Thanks for the reply. I think I have covered those 3 points:

Wiper delay relay active only if Position 1 (intermittent adjustable wipe) selected?

Wiper/wash switch is giving power in Positions (2 & 3) - checked input cables to park switch, so power is leaving there

Have rechecked all wiring connections are to the correct terminals.

If I'm being thick and missing something from your reply, please let me know

[Belle427]

Which ground are you using for testing?
I'd verify that's ok first.

[Jacqo le Jaq]

Thanks for the reply

I am using the Black (Earth) wire that connects to Terminal 1 on the park switch. I am getting 12V fine across that and the wires that connect to Terminals 2, 3 & 5 on the park switch

[Loubaruch]

You would be better using an earth completely seperate from the wiper circuit preferably battery -Ve.

[Murph7355]

Have you checked your wiper spindles?

With the motor cable removed from the car, and the wipers removed, do the spindles run freely (as in very freely) and are they the same both sides?

[Jacqo le Jaq]

Thanks for that information. I have now done this and checked everything moves freely. The wipers are now working OK and faster than before. I think this is because I stripped the mechanical assemblies down and thoroughly cleaned out old grease, reapplying lithium grease. This has undoubtedly improved the motion.

However, it seems the issue was electrical. The brand new original Lucas park switch sections were moving apart when clipping to the motor. I have since seen a YouTube video where this is glued together to prevent this occurring. I have not done this as I refitted the old park switch which was not coming apart and worked fine.

For the future if a replacement motor is ever needed, I come back to my question on whether the 14W or 16W variant of this motor would function ok, as the rest of the design is identical apart from a different angle crank gear (170 degrees on the Griff vs 100 to 130 degrees on other vehicle applications).I have heard that someone has 3D printed suitable replacement gears. This could be a solution or perhaps just refitting the existing Griff crank gear in the new wiper motor (if serviceable). I understand the Griff motor is 29W, probably upgraded due to the car's performance capability, but I can't see myself driving in a 'spirited' fashion if it's raining. The wipers themselves are not larger than other applications. Thoughts or experiences trying this?