tow relays question

joohn · **Posted:** Sun Aug 30, 2015 5:47 am

I have the tow relay on my 2005 Cherokee fail (5C021) it cost is £49 can I alter the wiring and use two normal relays ?

or change the wiring to use a another module?

To repair the old one I cant find a relay (GOODSKY - SAM-SH-109D) with a decent delivery time.

Thanks

PALiftedKK · **Posted:** Sun Aug 30, 2015 12:37 pm

spend the cash for the original relay. if you add on another relay, that's one more thing to break.

I cant imagine what the relay would be used for towing though??? :2cents:

unless you modified the power delivery back there...

WWDiesel · **Posted:** Sun Aug 30, 2015 1:29 pm

PALiftedKK wrote:

I cant imagine what the relay would be used for towing though??? :2cents:

unless you modified the power delivery back there...

I think the relays convert the separate turn signal and brake light circuits into one circuit for the trailer plug-in as trailers only have one bulb that provide both brake and turn signal functions. Our Jeeps have separate lights or circuits, one for turn signals and one for brakes. :wink:

View wiring diagram:
http://ww2.justanswer.com/uploads/Chekman/2011-02-19_024300_stop.gif

joohn · **Posted:** Sun Aug 30, 2015 7:31 pm

The relays work to light the trailer lamps so the flashers don't flash too quickly or overload the jeep,

There is 4 relays for - stop - brake - left turn and right turn, I found a lot of threads about the tail lamps not working.

If you have a rear flasher not working and your jeep is wired for towing it will likely be the relay that's gone behind the RH rear panel.

sent me mad for 4 days finding what was wrong.

Still would like a relay (GOODSKY - SAM-SH-109D)

PALiftedKK · **Posted:** Sun Aug 30, 2015 7:49 pm

joohn wrote:

The relays work to light the trailer lamps so the flashers don't flash too quickly or overload the jeep,

There is 4 relays for - stop - brake - left turn and right turn, I found a lot of threads about the tail lamps not working.

If you have a rear flasher not working and your jeep is wired for towing it will likely be the relay that's gone behind the RH rear panel.

sent me mad for 4 days finding what was wrong.

Still would like a relay (GOODSKY - SAM-SH-109D)

possibly. coil voltage is below 12v. you'd need to implement resistors and a few diodes on the coil and switch side. 4 diodes to be exact. at least with the handling capacity of 4 amps.

honestly, its less work and far simpler to use the original harness and or relay.

though if you really do want to go through with this, go with a solid state relay.

still questioning why a relay is needed on the 4 and 7 connectors. I have not looked into the pin layout on the trailer connector.

find relays that have DPDT (double pole double throw), the data sheet on the site looks Russian. do you have access to Advance Auto or AutoZone stores?

joohn · **Posted:** Mon Aug 31, 2015 2:44 am

The small GOODSKY relay is 1 of two on a small board only 1 has failed I could replace it easy, and the cost of one is less than $1 if I replace the unit 5C021 it will cost $90+

It is an easy repair and it would be as good as ne after.

Billwill · **Posted:** Mon Aug 31, 2015 10:04 am

joohn wrote:

I have the tow relay on my 2005 Cherokee fail (5C021) it cost is £49 can I alter the wiring and use two normal relays ?

or change the wiring to use a another module?

To repair the old one I cant find a relay (GOODSKY - SAM-SH-109D) with a decent delivery time.

Thanks

A relay is a relay....no way I would pay that amount of money.

Remove the failing relay and wire in a relay that can handle the same amperage on its contacts or use a higher rated relay.

If the relay has a diode across the coil then fit a new diode as well...make sure that the "stripe" on the diode lines up in the same direction as the original diode....remove the old diode in case it has shorted out. The 2005 circuit diagram shows that the relays have a built in resistor going across the coil...not a diode... but serves a similar purpose!

The diode, if used, stops back EMF surging down the line which can damage other components further back down the line towards the +12 volt relay coil activating power. :wink:

joohn · **Posted:** Tue Sep 01, 2015 6:01 am

The relay I require is on a board with lots of other parts only the relay has gone I think it smelt hot, I cant use any other as it must replace the old one on the board it is soldered direct to the 5C021 board.

Still cant put a picture of it on my post for some reason?

The link below shows the unit 5C021

https://www.google.co.uk/url?sa=i&rct=j ... 7965204205

Billwill · **Posted:** Fri Sep 04, 2015 3:36 am

joohn wrote:

The relay I require is on a board with lots of other parts only the relay has gone I think it smelt hot, I cant use any other as it must replace the old one on the board it is soldered direct to the 5C021 board.

Still cant put a picture of it on my post for some reason?

The link below shows the unit 5C021

https://www.google.co.uk/url?sa=i&rct=j ... 7965204205

Link not working!

You can remove the faulty relay...solder short sections of wire into the relevant positions ie, 85,86 87, 30 and mount the new relay nearby (double-sided tape) with the new wires soldered onto its terminals....maybe not the neatest solution but will work! :wink:

joohn · **Posted:** Wed Sep 09, 2015 2:46 am

I am on holiday at the moment but will do what you say on my return, thanks

tow relays question

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