Ad-HocXJ

I am having some trouble figuring out the details on converting my headlamps wiring to relays.

I am going to stick with the sealed beams for now, and the specs on them say they draw 35 watts (@ 12v). The H4 conversion beams are spec'd at 55/60 watts for low/high beams respectively.

On all the diagrams and "How-tos" they say to use 30 or 40 amp relays. And I get varying information on what size fuse to use. 10A or 30A for each relay.

I want to use micro relays for the headlights, one for low and another for high beams. I am pretty sure they are rated for 20 amps. The micro relays are: 72472M 4671168E SIEMENS (The standard ones for 97-01 Cherokees). -EDIT- Confirmed that the relays are in fact 20A

Doing the math I = P/V:
I = Current in Amps
P = Power in Watts
V = Voltage (V=12v)

The sealed beams at 35 watts come out at 2.5 amps or so, and the H4 high beams are 6 amps.

This doesn't seem right to me.

But information here says that each headlight only draws 10amps (for a 97-01):

Some people say the headlights should have 30 amp relays, some say they can be run by 20 amp relays. If someone could clarify it would be much appreciated!

00t444e

I got the wiring harness it had 30 amp relays and a 20 amp fuse to power both headlights. I am running 80/100 H4 bulbs with no problems. Two 100 watt bulbs are going to pull 17-18 amps.

cruiser54

Are you hell bent on building your own versus buying tried and proven kits for under $20?

Dumajones

Same question as Cruiser,,,why not just get a good kit.. Ive seen them for 15 bucks and under. But Im sure those are really cheap on the relays.

This is the one I picked up for my 2000 long time ago. Ive run 90/100w bulbs on this harness without any issues. Plus this is in the US not China
This harness is 22.50
https://www.ebay.com/itm/2-Headlight-H4-Headlamp-Light-Bulb-Ceramic-Socket-Plugs-Relay-Wiring-Harness-Kit/262483542712?epid=1973689229&hash=item3d1d3d02b8:g :FGgAAOSwQNRXLlAl&
vxp=mtr

This harness is 10 bucks straight from WunHungLo and his comrades... Im sure this one is junk..so be careful when looking on Fleebay for harnesses..Try your best to pick one that looks like they took care in the product . Or just get the one I listed..its proven to work great.

https://www.ebay.com/itm/H4-Headligh...laJSXQ&vxp=mtr

cruiser54

I've never paid more than $20 for a harness like the one above, have installed at least 10 of them, and NEVER had a single issue.

The issues are caused by poor grounding of the relays and not fastening them properly.

Dumajones

Would you get the china one for 10 bucks? I sure wouldn't.. Im sure they are going super cheap on everything.

Yes you can find them for under 20,,I Just picked that one,,
Fast shipping pulled me in lol

And totally agree..most problems are from bad mounting locations..and not grounding properly

cruiser54

Half the ones I installed were Putco brand.

Dumajones

Putco is good, My 95 has been running one for years.. Most problems people have with the Putco is like what you said.. Not grounding the relays proper(Needs to be grounded to shiny clean metal)
But the Putco harness is in the expensive range compared to the 20 buck harnesses.

Out of the few 20 dollar harnesses Ive installed. The 20 buck one has done just as good as the Putco.

cruiser54

I totally agree. And, it isn't yellow!!

Dumajones

Lol yep..That yellow on the Putco harness seems to stand up and punch you in the face, I didn't like that. I wrapped mine with black hockey stick tape where it was showing.

PCO6

- I installed a Putco in my MJ, reinstalled the grill and immediately said WTF did I just do? I took the grill out right away and wrapped the visible parts in black plastic wiring loom. The yellow looks nice under the hood though! lol

The harness came with the Jeep but hadn't been installed yet. It worked great so I got one for my XJ too. I realized later that it isn't the cheapest ... but what are you gonna do? I agree with the comments above re proper grounding.

jhc7399

WunHungLo lmao!!

I have been selling these for almost three years here on the forums.

https://www.cherokeeforum.com/f74/he...pgrade-219596/

I have never had one returned, they seem to hold up very well. I do not have any experience with the Putco but have had guys complain about the relays going prematurley.

Dumajones

Wow..Nice harness.. Looks well made. good price..
The relays on the Putco need a good ground. Most people having the relay issue is do to not having good clean ground.

Do the mounts on the relays need to be grounded to metal with your harness..or dont matter?


WunHungLo..Cruiser taught me that..He is a bad influence on me..lol

EZEARL

I don't know. That yellow on my Putco seems to go well with the forest green paint on my XJ. Only had to replace one relay in many years. Actually it works but won't activate unless you squeeze it. Right off I don't believe the relay mounts need grounding. BUT if I ever do replace the Putco it'll be with one of jhc's. Can't remember what the Putco cost me exactly but I'm thinking at least twice what jhc wants.

Ad-HocXJ

I am going to wire my own because I have an accessory fuse box that is a converted 01 OEM fuse box. I hate having random relays strewn across the engine bay.

Also some reviews on the Putco harness say that the manufacturing has changed, and is now dangerously thin wiring combined with garbage relays.