Power Steering Relay - USEFUL TIP!

Re: Power Steering Relay - USEFUL TIP! (kojab)

Sun, 14 Mar 2021 16:16:25 GMT

Interesting read.

Every time I go to start my SW20 the power steering pump runs for about 30 seconds.
Could this be the same relay at fault.

To be truthful I don't even know if the power steering is even working on the SW20.
I do know its it's much lighter to steer than my AW11.

Re: Power Steering Relay - USEFUL TIP! (Admin)

Sat, 13 Mar 2021 15:42:53 GMT

Hey everyone. I wasn't able to get it to work with the SSR. No matter what I did, the PS ECU didn't like it and kept throwing an error.
For those of you that are interested, here are the measurements for the input side of the working Toyota relay -

5.5V
680mA
7.7 Ohms

The SSR only draws 7mA so I thought that the ECU could be tricked by putting a 10 Ohm resistor in parallel with the SSR input. This drew 614mA and the SSR would switch OK and turn the pump on for a few seconds, though it would then turn off and the PS ECU would show an error. There is something that the PS ECU doesn't like though I can't figure out what it is.
I ended up putting in a high current 12V mechanical relay, and the 5.5V input seems to drive it OK and the PS ECU doesn't throw an error.
Here are some photos of my finished product -

If anyone wants to buy a near new SSR, it is $30 ($50 new) and I will throw in a mounting bracket for free! 😊

Re: Power Steering Relay - USEFUL TIP! (Admin)

Sat, 13 Mar 2021 11:19:09 GMT

Thanks mate. I'll give it a try later today.

Re: Power Steering Relay - USEFUL TIP! (Knightrous)

Sat, 13 Mar 2021 11:16:11 GMT

Admin
I have a bag full of MUR415 diodes. Will wiring a few of them in parallel be good enough? They are rated at 4A forward current.

Yes, that will be fine.

Admin
The current drawn by the SSR from the trigger circuit is significantly less than a mechanical relay. I'll try adding a resistor across the input terminals to generate some additional current from the ECU output.
Hopefully that will work.

Measure the resistance of the old relay coil and add a resistor in line with the input for the SSR, that should allow cars circuit to believe a normal relay is in place and prevent the error light. I assume this is similar to the case of installing LED indicators without resistors and they behave in the failure mode.

Re: Power Steering Relay - USEFUL TIP! (Admin)

Fri, 12 Mar 2021 21:21:03 GMT

The current drawn by the SSR from the trigger circuit is significantly less than a mechanical relay. I'll try adding a resistor across the input terminals to generate some additional current from the ECU output.
Hopefully that will work.

Re: Power Steering Relay - USEFUL TIP! (Admin)

Fri, 12 Mar 2021 21:07:37 GMT

I did what Rob did and just installed the 100A SSR from Jaycar. He didn't add a diode and it has been working fine for years.
Mine does work - however...
1. When I turn the ignition on, the SSR switches and the pump runs
2. It however doesn't stay on for a long as it did with the original relay
3. If I start the car, the pump runs for a few seconds though then turns off (earlier than it did before)
4. After it turns off, the error light displays on the dash. It never did this before.

The only thing that I changed was the SSR. It seems that the power steering ECU is sensing that something is wrong with the relay and then goes into error mode.
Could it be because the SSR is drawing less current from the driver circuit and the PS ECU doesn't like it?

Do any of you have an idea of what can be done to fix this?

Wiring the input of the SSR straight to the switched ignition 12V would work, though I would like the system to work in the same way as it did before.

Thanks

Re: Power Steering Relay - USEFUL TIP! (Admin)

Fri, 12 Mar 2021 09:52:44 GMT

I have a bag full of MUR415 diodes. Will wiring a few of them in parallel be good enough? They are rated at 4A forward current.

Re: Power Steering Relay - USEFUL TIP! (Admin)

Thu, 11 Mar 2021 22:48:31 GMT

How big does it need to be?

Re: Power Steering Relay - USEFUL TIP! (Knightrous)

Thu, 11 Mar 2021 21:56:10 GMT

Admin
Did you use a diode with your installation, @Knightrous?

Yes, a 'flyback' diode is a must for induction loads.

Re: Power Steering Relay - USEFUL TIP! (Admin)

Thu, 11 Mar 2021 17:18:49 GMT

Mine has finally decided to play up. It's a bit off-putting when the steering feel changes suddenly when you are racing around the track. I'll be visiting Jaycar tomorrow.
Did you use a diode with your installation, @Knightrous?

Re: Power Steering Relay - USEFUL TIP! (Knightrous)

Sat, 26 Mar 2016 15:59:34 GMT

Replace the relay with a Solid State Relay, you'll never have this issue again.
Jaycar stock a 30V 100A (accepts 4-32v trigger) for $50.

http://www.jaycar.com.au/Electromechanical-Components/Relays-%26-Accessories/Solid-State/Solid-State-Relay-4-32VDC-Input%2C-30VDC-100A-Switching/p/SY4086

I used these in a robotics application where we use to weld or melt the regular 12v 80A mechanical relays.

Re: Power Steering Relay - USEFUL TIP! (Matts_SW20)

Sat, 26 Mar 2016 12:02:58 GMT

Ah ok, saw some posts on other forums about cleaning the contacts for the ECU but not the relay. I would be so happy to see the aftermarket relay so I can get the same, it bugs me when something on my car isn't 100% haha.

Re: Power Steering Relay - USEFUL TIP! (Nik_Lee)

Sat, 26 Mar 2016 08:11:55 GMT

They are a sealed relay so you couldn't clean the contacts without destroying the relay.
I had the same problem with mine about 1 year ago and I persisted with cycling the ignition for a while until it just became too frequent and then I sorted it out by changing the relay, I found a very suitable aftermarket option and would be happy to show you next time you're at one of our local meets.

Re: Power Steering Relay - USEFUL TIP! (Matts_SW20)

Sat, 26 Mar 2016 00:13:51 GMT

Convenient timing for this post my 1990 Turbo just got the same problem for the first time the other day. I did the ignition trick 30 times and it worked but it did it again tonight :/ is there another fix like cleaning the contacts or something?

Power Steering Relay - USEFUL TIP! (robk)

Fri, 18 Mar 2016 20:28:57 GMT

I wanted to share a new trick that I applied successfully.

I just encountered the (very common) power steering relay problem on my SW20.
Out of the blue my power steering stopped working and the PS light lit up on the dash.

I tried the trick of cycling the key in the ignition many times but it didn't work like it normally does. I did it about 20 times with no luck.

The power steering relay (in the frunk on the strut tower near the fuse box) has 2 separate plugs. The smaller one has 2 small wires for the relay coil, while the bigger one has 2 fat wires for the contacts to the pump. I disconnected the smaller plug for the relay coil and connected alligator leads to each pin. I connected one alligator lead directly to the negative battery post. I took the other alligator lead then proceeded to rapidly tap it against the positive battery post. This allowed me to switch the power steering relay almost 100 times in little more than 10 seconds, which is much more effective than using the ignition key, plus it prevents other systems in the car from also being switched repeatedly.

It worked! My power steering worked fine after doing this.